once you get everything in place, make sure you do the automated tuning (YPAO) as it will help you much more than we can, since it can actually hear and adjust the room accordingly.
depending on what you're watching, you may not get much out of the rear as they are merely an enhancement, are typically quite a bit softer than the fronts, and depend greatly on whoever mixed the audio for that particular movie/show.
if you have Netflix search "Test patterns"
play season 1 episode 1
it will beep a couple times. (beep should be in time with the green arrow flash, so that can help you verify audio timing)
then say "left channel" and do a frequency sweep, then some pink noise.
it will work it's way though right, center, and sub (you'll probably just hear a rumble) before it moves to the surround channels.
make sure your volume is at a reasonable level before you start. (You really just don't want it full volume, as there is a slight chance it could cause damage) as long as regular TV volume is comfortable you should be fine.
If you just hear a guy counting, you're only playing the stereo track, and need to check the audio settings in the main settings app.
if you have an iPhone, you can also adjust audio timing between your speakers and the aTV.
go to the bottom of the video and audio section of the appleTV settings app.
it'll walk you through everything, but you need to take your phone close to the TV to start.
