using Godot;
2dog exposes the full GodotSharp API that we've grown to love and expect.
Write C# as you always do, in your game code and in your host code. Of course, you can also use GDScript, but only in game code.
Official Docs
I'm happy to wag my tail and send you on an adventure to godotengine.org! https://docs.godotengine.org/en/stable/tutorials/scripting/c_sharp