Didn’t you just ask basically the same question in another thread? (http://digitaldjtips.com/forum/threads/first-dj-set-questions.9260/)
Anyways, quick’n’dirty answers… if you’re using your controller with the house mixer you just plug the controller into one of the channels on the mixer with an rca-cable. Simple as that. No need to touch the house mixer after that, just make sure the channel your controller is hooked up to is active. You’ll do everything on the controller as per usual, but instead of hooking the controller directly to a PA, there’s just another mixer in between.
Home setup:
[controller]——>[speakers]
Club setup:
[controller]—–>[house mixer]—–>[house PA]
Regarding the CDJs, if you prepare your music in the Pioneer rekordbox software and put it on a USB, then no, you won’t need a laptop. But like I said in your previous thread, if you’ve never played on a cdj-setup before, don’t do it for the first time playing live.
Lastly, and I know I’ll probably take some flak about this, but if you one day hope to be a pro, learn to use the Pioneers. The mixtrack is nice and all, but it’s a toy compared to the real pro setups found in clubs around the world.