Just to pass along a couple details that I managed to remember...
There are two tapping screws that retain the upper part of the window to the door frame - remove these with a #2 Phillips (yes, that size is specific. They're easy to strip with a #1...)
The lower "post" (the vertical edge continues into the door shell, and doubles as the forward side of the window track) can be retained with bolts and nuts, but the ones I've seen have been retained with large rivets. Drill using a 1/4" drill bit (centre drill first, so it doesn't walk on you) and attach the new window using 1/4" machine screws and nuts. I used CRES hardware and nuts with Nylon locking collars (I've never trusted split lockwashers, and star washers are only marginally better. Nylon collar stuff is just fine - just replace it if removed.)
Run the main window down all the way to remove the vent assembly. You should not need to remove the main glass. The vent will tilt back to disengage from the main window pane, you can then tilt it toward the outside of the door shell and lift it straight up to remove it. Installation of the vent assy is the reverse of removal.
Save the fixed windows - someone may want to buy them from you, or you may want them later.