The vent window assembly goes into the door with only the door latch, window regulator, & (loose) glass. Then the upper/rear glass run goes into its channel, and the window is rolled up. After bolting in the glass stop and lower glass runs, the glass is rolled down to snap in the weatherbelts.

If there were door panels, they'd go back on at that point.

See also:

Owner caption November 2019 · Photo 134 of 147