Best thing they can do is advise you.
After all a fork and shock setup for one person can be crap for another, also set up can vary for sertain rides, depending how much you are prepared to learn about the set up.
I find it all quite easy to fiddle with.
first thing is sag, I go for between 20 – 30% sag, or even 40% sag on the scout.
But the rebound and compression, it depends on your fork and how you ride and the terrain, so no one setting will be correct for everything.
I susually work on wind everything off, then wind on all settings by a third. Then ride and get a feel for it. Personally I dont like a lot of damping, other people I know use a lot of damping.
I would recommend learning how it all works and take pleasure in your knob twiddling.