The first step is going to be to open your controller.
To do this the right way, you'll need a torx t-8 security screwdriver
. Or you can jam a micro flat head in on the side of the security nub and unscrew it until the security nub breaks off (like all of mine did) and then use a regular T-8 torx screwdriver.
Make sure you get the one in the middle under the battery pack and behind the sticker.