Choose where you're going to place your monitor. You'll want it in the optimum position to provide the best playback possible.
Connect one end of your jack-to-jack cable to the audio "in" port of your monitor.
Connect the other end of your jack-to-jack cable to the "monitor auxiliary out," "control room out" or "auxiliary out" channel on your mixer, depending upon the type you're using. You can also connect an active monitor directly to the sound card of your computer if you're recording electronically. You'll need the correct lead for your sound card's "out" ports; you can buy this from a computer hardware store or online.
Play a track and experiment with the position of your active monitor.