Help with door handle/mirror install

If remote mirror, that cable has a clip attaching it to a pinch weld. That clip and all other hardware is reusable.
These door panels have steel X wire clips in hard board that has become very brittle. Even when using the proper panel removal tool, damage can occur, including visible damage when trying to get them back in the holes. I'm not saying you'll need to replace those with modern plastic push pins but I always do.