well first you take your door panel, lay out what you want to do with it make some rings out of MDF to support your speakers, mount the rings to the door panel, stretch some sort of fabric that will retain resin over you door panel and make whatever design you want, soak the fabric in fiberglass resin, I like to do three coats, let it dry, bondo the hell out of it, sand, sand, sand, sand, bondo, sand sand , bondo sand, sand, sand, then stretch vinyl over the whole thing