Remove any trace of the old adhesive from the Pixel's case.

If you're reinstalling your existing display, be sure to remove any remaining adhesive from the back of your display as well.

Take special care to remove any small glass fragments.

After removing all traces of glue and glass, clean the adhesion areas with high concentration isopropyl alcohol (at least 90%). This will ensure a better seal for the display.

If your new display doesn't come with speaker grilles or a front-facing camera gasket, make sure to install those before applying display adhesive.