How do I remove / put on the chrome trim on a 85 Camino's doors?

Now I am no expert on all El Caminos other than what I know about my 4th Generation. Which chrome trim are you referring to? If it is the strip along the top of the door (bottom of window), then for my 4th gen the chrome is part of the exterior window felt assembly.

That would depend on which chrome piece you're talking about. The one up by the window is attached to the window felt and that would require unscrewing and pulling the window felt out, the one one tha door panel is a plastic piece covered in a "foil" to get that off pop out the retaining clip located around the edge of the door and alittle fanangling and it's off.