How do I use a c# library in unity?

I want to build a chat system using unity as the client and nodejs on the server using I am trying to use this c# client library for in unity but I can’t get it to work, I tried downloading the whole thing from github and pasting it in my assets folder, it threw a lot of errors. Please help

Hello @charlesonunze,
How do you use that library? Or what do you use for your system? I also need client for unity.

If anyone of you reaches here for the same question.

Have a look at Using .NET 4.x in Unity | Microsoft Learn