music shield help.

i am in the process of designing a system for my associates degree final project. i am using an arduino mega, an ebay 2.8" tft, and the seeed music shield 1.0. i need to use the touch screen to control the music shield playback. but i have to find a way to use an auxiliary input. i know in the data sheet for the chip it says input/mic but im not sure how to make it pass the audio through from an external device.?

also is there a way to display all the music files on the sd card in a list to be selected from automatically?

Maybe you can refer to this website( to fine more information

So,what method do music play automatically? Time or others?