Use a Phillips #1 screwdriver to remove the two 12.5 mm screws, four 5.5 mm screws, and six 7.25 mm screws.

Remove the two corner panels along the ends of the battery slot and this will expose another set of screws (1 under each panel).

Remove the remaining six 7.2 mm Phillips #1 screws hidden in the battery area and underneath the covers.