@Adam > In order to provide some help, I'll need to check that you've got things set-up properly first...
With music playing on deck 1 and 2, and signal showing on each of the channel meters, take the channel faders up to the top. Adjust the master output so you hear it on the speakers. Next, assign channel 1 to crossfader A, and channel 2 to crossfader B. Now move the crossfader back and forth, does the audio change on the master output as you move the crossfader?