Remove the SIM tray.
Using a plastic opening tool, carefully separate the back panel from the main body assembly of the phone. Be extra careful around the SIM slot or other weak areas.
You may encounter some resistance due to hidden locking clips around the inside edge of the phone. Not to worry; just move in one consistent direction around the phone as opposed to jumping from spot to spot!
Top to bottom, left to right, clockwise or counter clockwise, once we make it about half way around the device, the panel is easily removable by hand.