The game already has the official bot installed. You can just use these commands in the console. (press ~) bot_quota <# of bots> - sets the amount of bots bot_kill - kills all bots bot_add -...
If you bought the CD, put in in your computer, and it should be self-explanitory. Otherwise, if you bought it from the Steam store, you will need to install Steam and log into your account. Yo can...
Click "Include CPU players (bots) in this game" before start the gameORClick H (In game GUI) and click (add bots)ORClick ` to bring up the console and type in bot_add then click submit