Basics of GMod Server Development (?)

I am Co-Owner of my buddy Chris’s DarkRP server, and I noticed recently that the developers need a bit of help in updating the server’s content and such, and I thought I should assist them a bit. My question is; what knowledge is needed in order to develop a GMod server? (Preferably DarkRP) That question may seem unclear, but I can’t find any guides online on the basics of GMod server development. I know it involves Lua, and I have a bit of knowledge of Lua, but I want to know the basic console commands that I would need to know. Also; how do I make custom classes for myself and other users? How do I edit the F4 menu? How do I add workshop content such as custom money printers, notifications such as “THE BANK IS BEING ROBBED!”, etc.

Any help? I can go into further detail if this is still a bit unclear.

Thanks man, I’ll check it out.