Hi I am trying to help a friend out she just bought a truck and it has a Sony CDX-45 CD changer in it. However she doesnt know how to get it to play. I have gone to Sony's website and looked at the owner's manual however it is just installation manual no instructional information. I then spoke with live support via chat and told them my difficulty and that the manual doesnt help and they referred me to talk to a local install place. Can some one please tell me how to get this to play