The battery is glued securely to the bottom of the case with double sided tape

Use a plastic spudger to carefully pry the old battery from the case. This will take some time and patience, as the double sided tape is very strong

Remove the amber kapton tape and snip off the two main connectors to the battery circuit board

Dispose of the old battery in the right way and DO NOT throw it into the trash

Be careful when working with the battery and connectors and avoid creating a short between the two connectors