I disaree with this step. undo the two screws, and then the cable and connector assembly comes off the button assembly. my screen came with the same assembly. so you can just transfer the cable and connector assembly to the new button. The steps here are silent on how to connect the ribbon cable
The pictures here are very misleading. The ZIF lock tab is towards the back of the connector - opposite to where the cable comes in. you flip it up and over. The picture here does NOT show the lock tab released! when replacing make sure the white lines go right into the connector - you should almost not see them anymore.