Be very careful here. It is not a 'pop off' cover design. Special care should be directed to AVOID anything that may appear to cause a "bend" in screen.
Gently use fingernails (or if you have one, plastic pry), starting in the very middle location for each side (saving keyboard connector latch over area (bottom side) for the very last removal step).
Work your way from the inner middle on each side, slowly. Slide gently towards the direction of each corner (saving the lifting of actual corners themselves for the second to last step)). Careful not to break thin speaker wires that line the outside of the inner case.
The very last opening piece should be the "latch over" (where the keyboard pins connect).
KEEP IN MIND: The main key here is to avoid any potential "bend" of the screen. We save the corners until after working on the middle of each side to reduce pressure on the screen.
Do not force anything. If it is not coming off with gentle effort, you are likely doing something wrong (try another side middle).