After 2 calls to RDE to figure out how the molding worked, ( I didn’t remember how it came apart and I was expecting something more like a “U” channel.) I fit the molding on the glass and mitered the corners. Then slid the assembled unit into the quarter window frame. I mounted the main window frame, then put the front of the quarter window frame in place, slid the “H” channel between the quarter glass and the rear frame, and pushed and pried until it popped into place. On hind site it might have been easier to leave the rear frame unriveted until the last step, but it might not have helped given that I was working by myself.