I'm no artist, as you can see, but made a rough drawing to show to run tape line along top, behind door and in front of the angled body line at the back of car, this will help very much in aligning body lines, if you cut all the way to the rear corner it's much harder. Cut inside tape line with die grinder and thin cutoff wheel, along wheel well and door jamb piece, cut spot welds and peel off pieces, new quarter should have these. Borrow a metal crimping/flanging tool that crimps the cut edges in so new panel lays in when cut fo fit, after cutting to fit and makeing holes for spot welds, align body lines, secure with screws and clamps, tripple check to make sure it's right and make many spot welds! And do this with tires and suspension in, and on the ground, not on the rotissarie. This is one of many ways, works for me, just remember to leave the piece at rear corner. Here's a rough diagram, good luck!