How to apply back panel adhesive properly?

Just be aware that once you break the factor seal, you’ll lose liquid resistance. Usually back glass adhesive is cut in a way that kinda follows the contours of the frame of the phone although you’ll apply the adhesive to the back glass and then put the back glass on the phone. Also keep in mine you don’t need the adhesive to be perfectly cut but as long as you have adhesive along the edges it’ll hold. You can use a hair dryer or heat gun to head up the back and either apply pressure with a little bit of weight or clamps to help the adhesive stay on.