How to install new assemblies from NuGet packages in offline mode

I do not have access to Internet for couple of hours and I need to start a project using VS 2015 community version.

• Newtonsoft.Json
• Esri.ArcGISRuntime.WPF

I already have theses two assemblies on previous projects. How can I use those existing assemblies on my new project? Or is there any way to add them to my new project in offline mode?