Hey BSweeper - You might want to ask this in the 5th gen (or search the 5gen) forum next time for a quicker response. That said, change your source on the radio to "AUX" and then play your mp3 player. The "aux" input port effectively becomes the "speakers/headphones" for your mp3 player. Unless your mp3 player supports bluetooth, in which case, you' need to pair the device to your radio before you could stream it via BT.