Trim the crash
Carefully line everything up, is the block sqaure in the cover? Brush PVA glue OUT (start in center, brush to edges) Get glue on the top of the crash too. Carefully - VERY carefully roll the cover over and onto the endsheet.
I didn't realize how critical this part is and how difficult. Be VERY particular, because once you've rolled that cover over and onto the endsheet you will not want to lift it back off. Messy, messy and you are more than likely going to tear something.
Flip and repeat to back side.