If you want to replace your battery it's enough to peel the bottom part of the graphite film off the battery. If you want to replace your rear camera you need to remove it completely. In case you only want to replace the earpiece speaker or the front facing camera, you can leave it in its place.

Use a pair of blunt nose tweezers or a clean fingernail to carefully peel the black graphite film off the top right corner of the battery.

Fold the graphite film in direction of the selfie camera to get free access to the battery.