EK-TM4C123GXL: EK-TM4C123GXL audio input connection to ADC

I am novice and just completed an embedded training course with the TIVA C Series Evaluation Kit.  Trying to do a couple of projects which included linking the board to a standard audio MP3 input with 3.5mm jack.  Clearly did not want to simply attached directly to GPIO's ADC feature on the board in fear of damaging.  Can somebody advise how to do this and potentially with schematics or details of separate booster.