Hi, i am looking to learn about modding things such as Black Ops Zombies and Hosting Prestige/Challenge Lobbies.

I have looked through the tutorials but i could not find any in-depth ones about how you can host you're own Lobbies(obviously it wouldn't be as easy as that as everyone would be doing it) and how you can make a modded zombies game. So im wondering if anyone can give me any pointers or a helping hand to put me on the right tracks of where to start.

All help greatly appreciated and sorry if this is in the wrong section.