When the roof section is ready, you feed them up into the slot between the roof and the piece where the sun visors are. Then you tuck the back side into the top of the back glass gasket. This works much better if the rear window is removed and installed after the headliner. Then the two long pieces that go over the door go on. You screw them into the wood/composite strips that run along the inside edge of the door.

The front edge of these two pieces should have a fold in them. This rests against the same panel where the sun visors are.

The thin strip like pieces wedge in between the side of the windshield part of the cab and the windshield trim pieces. (does not apply to 1949-1954 small window trucks) There is no need dampen any pieces for proper fitment.