Open the case by lifting the non usb-port side slightly, then sliding the bottom shell towards the usb-port (see pics 1 & 2).

In pic 3, we can see the horizontal pins (red circles) that hold the usb-port side of the case on. Those are why we have to open the case on 3 sides and slide it off.

The blue square indicates the two wires that connect the button board to the main board. The yellow square indicates the battery wires, which are hidden under the RF shield.