Reply to Big noob that needs help with audio

So I recently bought a Numark Mixtrack Pro because I'm really interested in mixing/digital DJing, so I decided to start out really simple. I'm a little confused, however, with this while audio setup. I have some (shitty) speakers and (shitty) headphones. When I'm using the headphones, the crossfader doesn't work properly, it only lowers the volume of one track. Also, if I want to record a live mix while listening through headphones, how would I do that? Or is it even possible? I apologize for all these noob questions, but its been starting to bug me and I can't seem to find a solution yet. But that's probably because I'm not too bright when it comes to stuff like this. If you need to know any more information just ask!