We all have to learn this at some point - and no matter how long we've been messing with this stuff, there are still gaps in our knowledge.

Fortunately, the 990's auto setup should have you in pretty decent shape to begin with, but you might want to borrow your friend's SPL meter and run through the manual setup described in the manual. If you hit any snags, there are plenty of us around here who can lend a hand. Once you get the hang of it, you could then wander back over to your buddy's place and show him how it's done.