Unscrew the two (2) last Phillips screws that hold the motherboard. One is next to the black circle (vibrator) and one is next to the camera.
Super gently lift up the motherboard as the volume and power ribbon is clipped underneath. Lift it from the vibrator area so you may access to the clip. If the factory glue is correct enough, it will unclip by lifting the motherboard. JUST BE CAREFUL or buy a volume power with your screen.