This is the beginning process to remove or replace any functional component in the AirPort.
Remove the three 5mm T7 Torx screws from the back panel.
Remove one 5mm phillips screw located under the identification sticker. You will need to remove the sticker or make a hole to get to the screw.
Separate the bottom and top casings.
Remove the metal case from the top case of the AirPort, there are no screws holding it on.
Remove the four screws from the metal casing.