It stands for dialog pad,its the round thing with the arrows to the left of the controller.

1a) DONT GO ON XBOX LIVE, BUT GO ON THE SOLO MODE OR IT WONT WORK.
1b) Choose the difficulty that u can do anytin what u want.
2a) Go in bot optitions where u can decide what bots can buy.
2b) disable everything in the bot opitions.
3) select a level. (the level fastline is best so choose it.)
4) now EVERY BOT cant buy anything! too ur teammates.
5) only u can buy weapons.
6) have fun with that cheat.

NOTE: when u die, the enemy who killed u could pick up ur weapon. watch out then!