How to understand Github repository which in c#?

Hello all, I am mechanical engineer. I learn code python as much as needed. Now I am doing some project for which I need to use some repository in C#. I am new to c#, how can I learn as much as needed. could i get some tips for same.

Do you want to learn about Github, C# or the exercise C# repository structure?

If it is C# in general, you can try the docs.