Remove the six 3mm screws on the back of the motherboard with the Phillips Screwdriver #00 bit.

Remove the three 3mm screws on the back of the secondary board with the Phillips Screwdriver #00 bit.

Remove the ribbon cables connecting the boards to the other electrical components

Remove the ZIF connectors connecting the boards to the other electrical components

Some of the ribbon cables are secured with clips, simply pry up the clips before sliding them out of the pin connectors.