Radio installation

There is no a port. That same stereo is used in multiple models and has the controls for the optional CD changer and auxiliary input used on some of the other vehicles.
In this case that button only selects the CD for play if you are listening to the radio.

There are ways to add a jack to make it work but you need to remove the radio and solder in the parts. The other option is to use an FM modulator to send the signal into the radio.