C# Knowing STEPS to Save an image (with its timestamp AND its size) through Cloudflare protection

I want to use this script but I don't know how to use it

1. I downloaded Visual Studio Code + NudgetPackage + Jint
2. I have this script register under D:\PROJECT\Program.cs, but I don't know WHAT PARTS should I replace for the script to work, I need steps please.
3. I don't know where to put "static void Main(string[] args)", I put it at the start but I don't know if it's its place.
4. I will replace my " AAAAAAAAAAAAAA " by a real URL
5. I will replace my " BBBBBBBBBBBBBB " by a real USER-AGENT

That's where I am for now

What I tried:I tried to execute this script in Visual Studio Code, but:

6. "static void Main(string[] args)" seems to have "0 reference" there
7. With dotnet build, everything is OK (well, it seems to be)
8. But with dotnet run, these errors happened to appear

Trying..Unhandled exception. System.NullReferenceException: Object reference not set to an instance of an object.   at Cloudflare_Evader.CloudflareEvader.CreateBypassedWebClient(String url) in D:\PROJECT\Program.cs:line 71   at Cloudflare_Evader.CloudflareEvader.Main(String[] args) in D:\PROJECT\Program.cs:line 24PS D:\PROJECT>

using System;using System.Net;using System.IO;using System.Text.RegularExpressions;using System.Web;using System.Collections;using System.Threading;namespace Cloudflare_Evader{    public class CloudflareEvader    {        /// <summary>        /// Tries to return a webclient with the neccessary cookies installed to do requests for a cloudflare protected website.        /// </summary>        /// <param name="url">The page which is behind cloudflare's anti-dDoS protection</param>        /// <returns>A WebClient object or null on failure</returns>        static void Main(string[] args)        {            WebClient client = null;            while (client == null)            {                Console.WriteLine("Trying..");                client = CloudflareEvader.CreateBypassedWebClient(AAAAAAAAAAAAAA);            }            Console.WriteLine("Solved! We're clear to go");            Console.WriteLine(client.DownloadString(AAAAAAAAAAAAAA));            Console.ReadLine();        }public static WebClient CreateBypassedWebClient(string url)        {            var JSEngine = new Jint.Engine(); //Use this JavaScript engine to compute the result.            //Download the original page            var uri = new Uri(url);            HttpWebRequest req =(HttpWebRequest) WebRequest.Create(url);            req.UserAgent = "BBBBBBBBBBBBBB";            //Try to make the usual request first. If this fails with a 503, the page is behind cloudflare.            try            {                var res = req.GetResponse();                string html = "";                using (var reader = new StreamReader(res.GetResponseStream()))                    html = reader.ReadToEnd();                return new WebClient();            }            catch (WebException ex) //We usually get this because of a 503 service not available.            {                string html = "";                using (var reader = new StreamReader(ex.Response.GetResponseStream()))                    html = reader.ReadToEnd();                //If we get on the landing page, Cloudflare gives us a User-ID token with the cookie. We need to save that and use it in the next request.                var cookie_container = new CookieContainer();                //using a custom function because ex.Response.Cookies returns an empty set ALTHOUGH cookies were sent back.                var initial_cookies = GetAllCookiesFromHeader(ex.Response.Headers["Set-Cookie"], uri.Host);                 foreach (Cookie init_cookie in initial_cookies)                    cookie_container.Add(init_cookie);                /* solve the actual challenge with a bunch of RegEx's. Copy-Pasted from the python scrapper version.*/                var challenge = Regex.Match(html, "name=\"jschl_vc\" value=\"(\\w+)\"").Groups[1].Value;                var challenge_pass = Regex.Match(html, "name=\"pass\" value=\"(.+?)\"").Groups[1].Value;                var builder = Regex.Match(html, @"setTimeout\(function\(\){\s+(var t,r,a,f.+?\r?\n[\s\S]+?a\.value =.+?)\r?\n").Groups[1].Value;                builder = Regex.Replace(builder, @"a\.value =(.+?) \+ .+?;", "$1");                builder = Regex.Replace(builder, @"\s{3,}[a-z](?: = |\.).+", "");                //Format the javascript..                builder = Regex.Replace(builder, @"[\n\\']", "");                //Execute it.                 long solved = long.Parse(JSEngine.Execute(builder).GetCompletionValue().ToObject().ToString());                solved += uri.Host.Length; //add the length of the domain to it.                Console.WriteLine("***** SOLVED CHALLENGE ******: " + solved);                Thread.Sleep(6000); //This sleeping IS requiered or cloudflare will not give you the token!!                //Retreive the cookies. Prepare the URL for cookie exfiltration.                string cookie_url = string.Format("{0}://{1}/cdn-cgi/l/chk_jschl", uri.Scheme, uri.Host);                var uri_builder = new UriBuilder(cookie_url);                var query = HttpUtility.ParseQueryString(uri_builder.Query);                //Add our answers to the GET query                query["jschl_vc"] = challenge;                query["jschl_answer"] = solved.ToString();                query["pass"] = challenge_pass;                uri_builder.Query = query.ToString();                //Create the actual request to get the security clearance cookie                HttpWebRequest cookie_req = (HttpWebRequest) WebRequest.Create(uri_builder.Uri);                cookie_req.AllowAutoRedirect = false;                cookie_req.CookieContainer = cookie_container;                cookie_req.Referer = url;                cookie_req.UserAgent = "BBBBBBBBBBBBBB";                //We assume that this request goes through well, so no try-catch                var cookie_resp = (HttpWebResponse)cookie_req.GetResponse();                //The response *should* contain the security clearance cookie!                if (cookie_resp.Cookies.Count != 0) //first check if the HttpWebResponse has picked up the cookie.                    foreach (Cookie cookie in cookie_resp.Cookies)                        cookie_container.Add(cookie);                else //otherwise, use the custom function again                {                    //the cookie we *hopefully* received here is the cloudflare security clearance token.                    if (cookie_resp.Headers["Set-Cookie"] != null)                    {                        var cookies_parsed = GetAllCookiesFromHeader(cookie_resp.Headers["Set-Cookie"], uri.Host);                        foreach (Cookie cookie in cookies_parsed)                            cookie_container.Add(cookie);                    }                    else                    {                        //No security clearence? something went wrong.. return null.                        //Console.WriteLine("MASSIVE ERROR: COULDN'T GET CLOUDFLARE CLEARANCE!");                        return null;                    }                }                //Create a custom webclient with the two cookies we already acquired.                WebClient modedWebClient = new WebClientEx(cookie_container);                modedWebClient.Headers.Add("User-Agent", "BBBBBBBBBBBBBB");                modedWebClient.Headers.Add("Referer", url);                return modedWebClient;            }        }        public static CookieCollection GetAllCookiesFromHeader(string strHeader, string strHost)        {            ArrayList al = new ArrayList();            CookieCollection cc = new CookieCollection();            if (strHeader != string.Empty)            {                al = ConvertCookieHeaderToArrayList(strHeader);                cc = ConvertCookieArraysToCookieCollection(al, strHost);            }            return cc;        }        private static ArrayList ConvertCookieHeaderToArrayList(string strCookHeader)        {            strCookHeader = strCookHeader.Replace("\r", "");            strCookHeader = strCookHeader.Replace("\n", "");            string[] strCookTemp = strCookHeader.Split(',');            ArrayList al = new ArrayList();            int i = 0;            int n = strCookTemp.Length;            while (i < n)            {                if (strCookTemp[i].IndexOf("expires=", StringComparison.OrdinalIgnoreCase) > 0)                {                    al.Add(strCookTemp[i] +"," + strCookTemp[i + 1]);                    i = i + 1;                }                else                    al.Add(strCookTemp[i]);                i = i + 1;            }            return al;        }        private static CookieCollection ConvertCookieArraysToCookieCollection(ArrayList al, string strHost)        {            CookieCollection cc = new CookieCollection();            int alcount = al.Count;            string strEachCook;            string[] strEachCookParts;            for (int i = 0; i < alcount; i++)            {                strEachCook = al[i].ToString();                strEachCookParts = strEachCook.Split(';');                int intEachCookPartsCount = strEachCookParts.Length;                string strCNameAndCValue = string.Empty;                string strPNameAndPValue = string.Empty;                string strDNameAndDValue = string.Empty;                string[] NameValuePairTemp;                Cookie cookTemp = new Cookie();                for (int j = 0; j < intEachCookPartsCount; j++)                {                    if (j == 0)                    {                        strCNameAndCValue = strEachCookParts[j];                        if (strCNameAndCValue != string.Empty)                        {                            int firstEqual = strCNameAndCValue.IndexOf("=");                            string firstName = strCNameAndCValue.Substring(0, firstEqual);                            string allValue = strCNameAndCValue.Substring(firstEqual + 1, strCNameAndCValue.Length - (firstEqual + 1));                            cookTemp.Name = firstName;                            cookTemp.Value = allValue;                        }                        continue;                    }                    if (strEachCookParts[j].IndexOf("path", StringComparison.OrdinalIgnoreCase) >= 0)                    {                        strPNameAndPValue = strEachCookParts[j];                        if (strPNameAndPValue != string.Empty)                        {                            NameValuePairTemp = strPNameAndPValue.Split('=');                            if (NameValuePairTemp[1] != string.Empty)                                cookTemp.Path = NameValuePairTemp[1];                            else                                cookTemp.Path = "/";                        }                        continue;                    }                    if (strEachCookParts[j].IndexOf("domain", StringComparison.OrdinalIgnoreCase) >= 0)                    {                        strPNameAndPValue = strEachCookParts[j];                        if (strPNameAndPValue != string.Empty)                        {                            NameValuePairTemp = strPNameAndPValue.Split('=');                            if (NameValuePairTemp[1] != string.Empty)                                cookTemp.Domain = NameValuePairTemp[1];                            else                                cookTemp.Domain = strHost;                        }                        continue;                    }                }                if (cookTemp.Path == string.Empty)                    cookTemp.Path = "/";                if (cookTemp.Domain == string.Empty)                    cookTemp.Domain = strHost;                cc.Add(cookTemp);            }            return cc;        }    }    public class WebClientEx : WebClient    {        public WebClientEx(CookieContainer container)        {            this.container = container;        }        public CookieContainer CookieContainer        {            get { return container; }            set { container = value; }        }        private CookieContainer container = new CookieContainer();        protected override WebRequest GetWebRequest(Uri address)        {            WebRequest r = base.GetWebRequest(address);            var request = r as HttpWebRequest;            if (request != null)            {                request.CookieContainer = container;            }            return r;        }        protected override WebResponse GetWebResponse(WebRequest request, IAsyncResult result)        {            WebResponse response = base.GetWebResponse(request, result);            ReadCookies(response);            return response;        }        protected override WebResponse GetWebResponse(WebRequest request)        {            WebResponse response = base.GetWebResponse(request);            ReadCookies(response);            return response;        }        private void ReadCookies(WebResponse r)        {            var response = r as HttpWebResponse;            if (response != null)            {                CookieCollection cookies = response.Cookies;                container.Add(cookies);            }        }    }}