Question about an external mp3 player

Hi guys,
The other day I was at a gig and somebody came to me and ask me to play a few songs with their mp3 wich was an itouch and I just couldn't connect it.. I felt bad for that person and I dont want that to happen again...
so, How do u connect it to the tractor software and be able to play it?:confused:

Manual

Connect a 1/8" plug to RCA cable into either Deck C or Deck D input on the rear of the S4. Then, go into Preferences / Decks / Deck Flavor, and select "Live Input" for the deck you want to use for the external source. Switch on rear should be set to "Line" level input.