Dear new & confused:
I just got the DJ Discover System for Christmas and I was in the same boat as you, but once I figured out how to move the audio tracks to the DJ Discover system, (they have to be MP3 files, not Windows media) I was up and going.
My 13 year old son put the same song on both decks and experimented with scratching, reversing and lots of other special effects.
I used to DJ with two turntables and had pretty good results matching songs by their BPM (beats per minute). This system does all the work by displaying the BPM, which should be a good place to start with your mixing.
Hope this helps!
Diva Sean Sean