Place the point of a spudger in the small hole on the side of the rear case.

Use the spudger to push the rear case away from the housing to create a small gap. Use steady force to separate the two parts.

Steady the rear case with a finger to avoid it suddenly popping open and damaging the flex cable.

Don’t open the rear case all the way just yet. It is still connected to the motherboard with a thin flex cable.