I would call and ask how that works for a spring admit.
But normally if you want guaranteed on campus housing, you have to committ to Pitt by May 1 and pay housing deposit by the deadline on your housing contract, which will be mailed to you.
If you accepted a spot on the waitlist, you might still have a chance to be accepted for fall, so make sure to find out what you need to do if you want to live on campus.
A few weeks after paying enrollment deposit you get a housing packet in the mail.
It explains different freshman residence halls, LLCs, meal plans.
It has info how to get to your online housing application and pay your housing deposit.
You can put roommate preferences and a few dorms in order of preference.
In July the housing assignments are emailed to students.
I don’t know much about Holland but I think a freshman especially would benefit a lot from living on campus.