Remove the arm rest piece gently sliding the arm rest forward. Disconnect the blank tray and replace with the BMW Eject Box that includes the telephone pairing button
If you BMW was built after March 2002 production the bluetooth antenna will mount under this arm rest in the location shown
Snap the new Eject box in place and connect to the factory wiring connectors under the arm rest at the top of the plastic panel. If your BMW was a 2002 or earlier build date the connectors are located under the plastic trim panel at the bottom of the compartment.