The regulator and motor assembly is placed back into the door and the plastic slides are lined up in their respective channels.  A little grease on the slides and channels  will help keep the windows operating smoothly.  

The regulator assembly can be reinstalled using 1/4 inch rivets like the factory (right photo) or 1/4 inch bolts and nuts (left photo).  For most of us, getting hold of a rivet gun capable of handling 1/4 rivets is out of the question.

With the regulator reinstalled, all that remains is reattaching the liner and reinstalling the door panel.