Take the back cover and battery off

Use an exacto knife or just peel away the sticker to reveal the screw hole circled in the photo

Unscrew the screw

Use your fingernail or something similar to wedge the bottom of the housing apart

There will be resistance from the top part of the housing, as depicted in the second photo, there are four pieces from the top and bottom housing that hold onto each other.

Apply horizontal pressure and press from the mouse wheel to slide the top and bottom housing apart.