You have to remove the B-pillar covers, side scoops and side skirts. This will expose the front bolts of the quarter panel. Remove these bolts, plus the ones along the top edge of the panel and the ones securing it to the rear bumper. It's something like 14 bolts total- all 10mm.
Looks like an easy repair to me, doesn’t require replacement. I personally wouldn’t replace it so it’s all original parts. It’s a 5-7 hours body repair. Just find a fiberglass specialist, usually places that work on corvettes.