Take note of which wire goes where (black wire below red wire in photo).

In gold writing, 'bat+' indicates the positive terminal (location of red wire), and 'bat-' indicates the negative terminal (location of black wire).

To remove the wires from their terminals, use a soldering iron and a solder sucker.

Refer to the ifixit solder guide to learn more about how to solder.

Attach the black (negative) and red (positive) wires of the new/replacement batteryrespectively to their terminals by soldering them.

Position the battery in it's original location, secure with glue.