How to install Nuget package using windows command line in C# project?

I have downloaded NuGet version - 5.1.0 and tried to install one of the package - log4net using cmd. it failed. below is error -

Here, ClassLibrary1 is C# project where I have to add log4net package. I don't want to use NuGet Package Manager Console option available in Visual Studio.

Did I write correct command?