Plug the D3 into a USB port on your computer (If possible, pick the higher speed port), and plug your headphones, powered speakers, or stereo system into the minijack output at the end of the D3. If using a Mac, go to System Preferences/Sound, and select "Audioengine D3". If you're using a PC, no setting changes are needed as the computer will automatically find the USB driver. Now play music from iTunes or your favorite media player and that's it - setup really is that easy.