did i do this right?

i started my interior dtarted today, and i was wondering if i did it right. Heres the thing, im doing my interior in fiberglass, i mean everywhere. I tapped down by the door, where i took off the old plastic trim, and tapped the rest of the plastic trim arond the door and in the back, over the panels.

My question is this, after i put the fiberglass on, do i leave it on, sand, prime and paint, or do i take it off, revealing the mold, sand , prime and paint, then put it back on. IF I HAVE TO TAKE IT OFF, HOW WOULD I PUT IT BACK ON WITHOUT WRECKKING IT THANK U AND PLEASE HELP

I WOULD'VE TAKEN PICS BUT I ONLY HAVE 2 K LEFT OF UPLOADING SPACE. IF U CAN TELL ME ANOTHER WAY TO UPLOAD THEM, ITT BE A BIG HELP