Reply to Midi-Fighter 2 deck setup w/ mixer

I have 2 questions. I have a numark 2 channel mixer, a numark dj io soundcard, 2 midi fighters, and traktor pro. I know that the 2 midi-fighters plug in usb into the ports of the laptop along with the soundcard.

But where do I put my cables from the soundcard to the mixer? And the what outputs on the mixer do I use to plug into my PA speakers?

Obviously I'm a begginer so if anyone can answer these 2 questions it would help alot.

Thanks!