During reassembly, it may be a bit of a challenge to reinstall the AirPort/Bluetooth card as the socket is on the underside of the logic board.

The AirPort/Bluetooth card socket is located a few centimeters below and to the left of the right speaker connector (highlighted in red), on the opposite side of the logic board.

If the AirPort/Bluetooth card is properly seated, its screw holes should align with those on the logic board.