Last cable that needs plugged in is the audio cable for the speakers on this monitor. This cable is keyed with a set of 'rails' on one face of the plug so that it can't be plugged in backward. Hold the back piece in place as if it were a hinged on the right side. Also be sure to route the video cable out the correct hole in the back as well( out the biggest hole). Once the audio is plugged in you should be able to lower the back in place and align it.