mixer

So I saw these 2 dudes DJig b2b Each one had their own akai mpd226//they're own laptops// and shared one djm mixer How exactly does this kind of DJing work? What's the djm mixer for If they're using Ableton and a launch pad? I've just used decks Sorry for the novice question, thank you...

Just got one of these, seems like a wicked bit of kit. due to my current living arrangement, I've been mixing with no output/speakers on my numark mixer, so basically just music playing through the headphone, using channel faders and what not. I hope I'm being stupid and there is still a way...