Using a 2.5mm allen wrench, remove the 4 bolts holding the lock cover in place:
Remove the lock cover:
Remove the 2 Philips screws that hold the lock in place and remove the lock.
Install the new lock.
Test the new position with the battery with the lock cover removed.
If the lock won't secure the battery, remove the battery, loosen the lock and shift it to the left or right. Moving the lock to the right will make the fitment tighter, while moving it to the left will make the fitment looser. Even very small changes have a large impact on how well the battery fits.
Once you find a position that secures the battery to the bike, replace the lock cover and the 4 bolts that held it in position.