Remove the battery.

To install a new battery:

Use a spudger and tweezers to remove all the old adhesive from the battery recess.

If your replacement battery doesn't have adhesive pre-installed, put strips of thin, double-sided tape on the logic board (not directly on the battery) where the old adhesive was. Do not remove any liners yet.

Reconnect the battery cable press connector to its socket on the motherboard.

Put the battery connector bracket into place and install its screw. Make sure the metal arm goes over the battery press connector.

Remove any liners from the battery adhesive or double-sided tape.

Firmly press the battery into place to secure it with the adhesive.