With the advance of new technologies, the DJ can now perform with a laptop, digital music files and/or a controller just as if she had two turntables and a mixer. The connections are relatively the same, just a change here and there. It is a much more compact and easy set-up to maintain. Although having less equipment might mean less hassle, you still need to know how everything talks to each other. Connecting a laptop to a DJ mixer is the easiest part. It's the DJing and mixing that takes practice.
Locate your laptop's sound card. Almost every computer has a 1/8-inch port -- usually used for headphones -- located on either the right or left side of the computer. Plug the audio cable into it.
Plug the RCA end of the audio cable into the "line-in" ports at the rear of the DJ Mixer. There are usually two different ports for cables in the back of these mixers. The best sound quality for the laptop will be the "Line-In" ports. If using turntables, you would plug the RCA ends into the "analogue" ports.
Plug your headphones into the "headphone out" or your monitors into the "line-out" on the rear of the mixer. Now you can monitor your mix.
Play a track on your computer to check the levels. You may need to adjust your audio properties so you hear music coming from your headphones or your computer monitors. In Windows, go to "control panel," select "hardware and sound," then "audio devices." Select "properties" and choose "stereo" or "audio-out."