How do I use a MP3 player in my Ford Expedition?

I have a 2006 Ford Expedition. The owners manual references playing my MP3 player through the entertainment system, but I have no idea where or how to connect it. There are no receptacles on the face of the Radio/CD Player. However, there are MP3 control buttons on it. Someone please help.How do I use a MP3 player in my Ford Expedition?Our 07 fusion has the controls to get to an aux port also but we did not get the package that has this feature. I thin you can hook something up to the back and add this yourself. You may have the controls but not the hookups.How do I use a MP3 player in my Ford Expedition?yea dude my 06 explorer says the same thing and i also have the buttons but there is not mp3 capability to be found. must be an add on that you CAN get but didn't at time of purchase. i mean, i didn't buy mine because i got it from my parents and i'm only 17, but i've tried to figure it out and can't. i resorted to buying a fm transmitter (which i hate and has terrible quality), and am now just turning to buying a new head unit. if you have the money, you should probably just get a head unit with mp3 capabilities because it's gonna work sooo much better than a fm transmitter which produces terrible quality music. i think i'm going to get the alpine cda-117 for about 250$ which has great ipod controls, but idk if you are willing to spend that. well whatever you choose, good luck, and i hope you are satisfied.