Remove the battery.

Peel up and/or scrape away any remaining battery adhesive before cleaning the battery well surface with isopropyl alcohol and a lint free cloth.

If you used isopropyl alcohol, wait ten minutes before installing the new battery to allow the alcohol to completely evaporate.

During reassembly, if your new battery doesn't come with pre-applied adhesive, apply some to the well. Then, firmly press the new battery into place.

Do not reuse the battery after it has been removed, as doing so is a potential safety hazard. Replace it with a new battery.