Once the black plastic is removed, you should be able to see the button control panel. This is the green board with the white circle in the middle.

Use the tweezers to pry this panel from the main board.

NOTE: There are three small screws connecting the button control panel to the main board. These are covered by black plastic and cannot be unscrewed with a screwdriver. If enough force is supplied when prying the button control panel free, these screws should come off with the panel .