so my boat has a sony head unit,I know nothing about mp3 stuff.When I turn on my stereo,MP3 scrolls across the front.So how do I listen to a MP3 player on it?Is there a usb port on the front?A spot for a memory stick,like my kids 50$ MP3 players?I see sony has a removable face plate deck,that you actually take the face,plug it into to you PC and download music right into the face!...without my boat being here,Im trying to figure this out.MY wife new cell phone has a MP3 player in it,200 songs or something,how do I play this on the boat???