I finally gave in to temptation and purchased a Bushmaster XM-15E2S.  It's sweet, a well crafted machine that controls and aims explosions, and will have a longer life span than I will. Most of my shooting will be between 100 and meters. So I was wondering  

How do I switch between he smaller and larger aperatures for the sights on the carry handle?

I would feel very foolish if I managed to damage this instrument by pushing or pulling on the wrong thing.

Any other advice for a newbie ?

TIA

jb  

Just flip it forward....

Although I have never used the Large App on my rifle.

It might be a little stiff the first few times.

Yup. That easy. Put a drop of CLP on windage adjustment screw that holds the apeture in place.
Come to think of it.....I've never used the large Apeture either!

welcome aboard.  like the guys above said... just flip it up or down.