Use tweezers to peel away any remaining adhesive from both the rear panel and the phone's chassis.

Clean the adhesion areas with high concentration isopropyl alcohol (at least 90%) and a lint-free cloth. Swipe in one direction only, not back and forth. This will help prep the surface for the new adhesive.

Peel away the replacement adhesive's liner, align it with the back of the phone, and press it into place.

Remove any remaining liners, and replace the rear glass panel.

After installing the rear panel, apply strong, steady pressure to your phone for several minutes to help the adhesive form a good bond, such as by placing it under a stack of heavy books.