Removing the back cover will invalidate your warranty.

You may use your fingers, or a spudger. Be careful not to break your cover OR your fingernail. Removing the cover requires good judgement.

The goal is to separate the black from the silver. Start in a corner, or a flat edge -- whichever works best for you. Remember to not use too much force.

Once you start the initial separation, keep going until you free one edge. The goal now is to free three edges of the rectangle.

If your progress stops on one side of the rectangle, go to the other side and try there.