Load a track on any CDJ and click the play button.
On the mixer, turn the channel fader down and press the channel cue button.
Move either hand next to your ear and click the trigger button to activate your virtual headphones.
On the phones icon on the lower left of your mixer, the light indicator will show which side of your virtual headphones is activated
To hear both master and cue across both headphones, click the trigger next to both ears. This will allow you to mix using the Mixing knob to adjust both cue and master levels.