Reply to Possibly the stupidest question ever asked

Hey guys, I'm predominantly a Digital DJ using MIDI Controllers.

I'm looking to get more and more into CDJs and the new pioneer video tipped me over the edge.

I want to start off fairly cheap, say CDJ400 or something like that.

How would I play the music off Traktor? I understand that I have to connect them through HID to the laptop, but I'm unsure about what to do with the mixer. Do I even need a mixer or can I just use my S2 as the mixer? I guess I just really get confused by CDJs.

What are the main things I need to know?

Thanks for putting up with me