Hello Thiengairrue73
The SBB Travel Center and the SBB Luggage Office is one and the same.
It is located one floor above the airport’s train station, which are both part of the terminal building.
Simply follow Bahn/Train signs when you are leaving the baggage hall / customs. You can’t miss it: you cross the street, you enter the building at the opposite side, you go one floor down, there you are.
Kind regards,
Roland