run the main outs from your mixer into your line in on your sound card, then you have to take the line out on your sound card and go back into your mixer, you can go about this different ways, the way i did it was to go into the tape inputs on my mixer, with it hooked up that way i can send the audio coming out of the computer to my monitors or headphones without having it go through the main outs back into the computer and be re-recorded when i'm trying to do an overdub. go into your audio settings and click line in and set the slider about 50 to 75% up. go into cool edit and click record on the track you want to record and then click on the input of the track and make sure its set up to accept the line in as the input. i know all of that sounds confusing but its really easy once you do it/