BOLERO HEAD UNIT USER HERE in one of the media menus is an option to turn on the aux. it's a tick box option. maybe the default doesn't have the box ticked. but when you scroll to the bottom of the the specific menu you'll see the greyed out aux option, tick it and it will enable you to connect mp3 player via 3.5mm jack cable to the aux connector in the cubby hole with aux and usb connectors, and you can play your mp3 player connected via a cable. you'll see aux appear as an option for input on the bolero screen once you've enabled it. up the volume in the player and also select the option for increased volume for the aux connection ( i think there are 3 setting low, medium and high ? ) that way you get a good volume without having to turn the volume right up on the mp3 player. i spend ages trying to find out how to connect eventually found it after going through every menu on the infotainment unit. my last journey was a pleasure playing my mp3 player instead of having to fiddle round with the cd player and i knew exactly how to use the mp3 player and get what i wanted quickly and efficiently.