As Greg started in the previous step in the comments, there is a singular small screw in the very bottom of the battery compartment holding the shutter button assembly in place, do not try to force the shutter button assembly up, make to remove that screw first (shouldn't be hard to take off).
DO NOT “just lift the motherboard"! The motherboard is soldered to a daughterboard for the power button and for the battery compartment. If you do forcibly lift the motherboard you will rip some solder pads off. You need to desolder the motherboard from the daughterboard FIRST before attempting to flip up the motherboard. AFTER desoldering the motherboard there is a singular screw holding in the board in the top left, remove that too!