Sound doesn't work ?

I have a Numark iDJ3 and my sound didn't work. So I changed the sound output to my laptop instead of my amp, and that worked. But the sound that's supposed to go to my headphones so I can cue up my next song doesn't work .
I'm a complete noob at this haha .
Any answers ?
I'm a complete noob at this haha .
Any answers ?