I recently purchased this chair on ebay. Picked it up thinking it should be pretty simple. It has a battery pack in the back of it and on the side of it, it has an on/off switch and a plug hole with the word 'speakers' on it, thats it. To plug the MP3 player (or anything else for that matter) what do I put in the speakers plug hole? My MP3 player only has a charger and phones. I don't get it. Either I am having a blonde moment or I need an extra cable. Anyone else have one of these who can help?