Background
The top overhangs of the bedside walls are stabilized by the flying buttress and rectangular wheel well to bedside braces.
Refer to tailgate preliminaries discussion. Before installing braces, put the two aluminum tailgate parts together — the inner frame and the outer skin — with the bottom hinge and top latch parts. Install the two latch strikers on the top of the bedside wall rear. Attach the tailgate and latch it closed.