Make sure all necessary pieces are accounted for in your manufacturer's shower door kit. Some pieces may need to be customized. In our project we had to round off the edges of the aluminum molding so they would fit perfectly into the radius of our fiberglass shower. File it down with a metal file.
Screw one side of the door frame into place on one side of the shower doorway (Image 1) and then dry fit the other side of the frame (Image 2), then the top of the frame into place. Screw in the other side of the door frame (Image 3).
Once everything is screwed and snapped into place, the roller wheels go on the doors and the doors themselves are lifted into place (Image 1). The interior door goes in first, and then the exterior door is installed from the bottom up. Install the handles and the rubber stoppers (Image 2).