The Bell Services desk is on the left side of the portico as you walk towards the front desk from the parking area. It is manned most of the day, but if you arrive late evening, just let the desk know you'll want assistance with your luggage and they will contact the Bell staff.
There are only 3 buildlings with elevator access (Bldgs 62, 63, 64)- so I'd plan on asking Bell Services for help. They are great and will be happy to assist.
Enjoy!