If you are not staying on campus, you can pick up your parking passes and/or meal cards at the SSV lobby during early registration or in the conference center during standard registration.
If you are staying on campus, you can check into your respective dorm in the lobby of that dorm starting at noon on the day that you are scheduled to arrive. There will be an IIT representative manning the front desk of each of the dorms. They will have your room key, meal cards, and parking passes with them. If you are arriving early and need to check your bags, try checking into the dorms anyway… most likely they will let you in.