Remove the retaining ring and the D-pad.

The retaining ring is clipped in. Lightly pull back and up to remove.

Make sure that the top of the retaining ring is detached before trying to remove it completely so as not to deform the part.

Remove the bumpers by pushing down on the ends and lifting outward to unclip them. Then, holding from the middle, wiggle the rest free while pushing the home button down.