Making my first module

I’d like to ask for help. Since the old wiki is down right now, I’d like to ask for some help on creating a module.
Can I use C# to create a module?
What are the basic things I need for a module?

Thanks in advance

C++, you should search around online or in existing module source codes for the requirements.

Can you even make dlls in C#?

But as Wiz said, you’ll need C++, along with the source SDK. Since Valve doesn’t update regularly, use AlliedMods’ gmod SDK, here.