How do I make a .cs file?

[Flubbman]

I'm working on a print, but it says I must have a server.cs file. How do you create .cs files? Just give me a quick answer and then I'll lock.

[Ad Bot]

[Doomonkey]

Save something as .cs, or copy a pre-existing .cs file and edit it.

[KoopaScooper]

When the save box comes up to save it, select to save as "All Files", and save it with the filename "server.cs".
That's all you have to do.