Turn computer so that the hinged side is facing up.

Use the plastic opening tool to pry open the back plate.

Drag the plastic opening tool along the edge from left to right and use a second opening tool to pry open the top right corner.

Repeat the 3rd step for the other side.

Repeat on Left and Right sides of the system. There are two points in the middle (on the left and right sides of the center screw) that will release with slight lifting pressure.

You should be able to hear a pop when prying open the corners.