Which edges do you want rounded/beveled/etc? You can ignore this if you want all edges square.
The Dark Gray "A"s comprise the top. A1=back, A2=right, A3=Front, A4=Left
The Black "C"s comprise the bottom, and the same rules apply.
The Light Gray "B"s signify the corners. B1=back left, B2=back right, B3=front right, B4=front left