Beginner tutorials for C# for Visuall studio?

I’m looking for tutorials on what I can do with the compiled CS solutions?
I’m trying to get a existing solution to reference to the complied solution in visual studio.

There is a *.csproj in this example repository which I presume can be opened in VS.
For generating externs for use with Haxe.
Most Haxe users use Visual Studio Code rather than other c# related products.
Sorry perhaps my answer is not helpful I don’t often use haxe c# but creating mono on a mac with Haxe seemed to work well.

I am absolutely not an expert on CS but I have tried to document some Haxe and CS in some of my quests to understand some targets. I tried Haxe and Unity (C# related) and a quick documentation of the system languages in Haxe (including C#)

Both repos have a website, it might give you an idea how to start.