It should have given you a code to activate them. Where did you pre-oder from? I preordered from gamestop, and the 25 digit code was on my receipt when i picked up the game. Mine only came with the catacombs though. To input the code(s), on xbox you hit the guide button, scroll all the way to the left, and there should be a "redeem code" button. On playstation i'm not sure, but it's probably something similar.