Risingroad

I purchased a 2019 Chevy Express passenger van 3500 and am converting it into a camper van for boondocking. I want to remove the plastic inside liners, or whatever it's called, and I see there are some pins attached to underneath the liner hooking to the metal rib. How the heck do I get those pins out of there if I can't get underneath the plastic liner? Thank you so much for any advice.