Using a spudger, start prying the case apart by working around the edge slowly.

Be careful not to damage any of the latches that hold the back panel in place, especially if you are using a metal spudger.

While prying, be careful to not lose the power and volume buttons; the case is the only thing holding them in place so they will easily come out once the panel has been removed

Be careful to not damage the speaker cables, they will still be connecting both panels.