I'll try and explain - but you may need to speak to the dealer.

1. Key in ignition but not turned
2. Open the leater top lid of the center arm rest (where there is room for a handset)
3. There is a button at the front
4. Press this button (hold it down)
5. Flick the key once so everything starts (apart from the car)
6. Release the button and the screen should say "PAIRING MODE"
7. This is now in pairing mode

Once paired - turn the car off (key out of ignition) and turn it back on - this should work now.