This is how the key pairing process is described in the user manual:
Note: Maximum time allowed for synchronising is 30 seconds.
1. The normal key (= the one without remote) is used to activate the ignition, and the key with the remote control is the key to be programmed.
2. Check that the car is open before commencing programming.
3. Place the key without remote control in the contact inside the steering and ignition lock.
4. Use the key with remote control and mechanically lock the vehicle from the driver's door.
5. Open and close the driver's door lock mechanically, using the remote control key.
6. At the same time press the open button on the remote control key.
7. Complete the procedure by removing the key from the contact.