I just bought a rifle with one on it. exactly how
The adjustment on the front eye PC is your zoom.
for your wind edge you have a series of numbers.
some scopes differ some read 5,10,15,etc
some read 1,2,3,4 etc, the # are estimated wind speed,left or right.if the wind isn't blowing set it on 0.
for your elevation you will have a series of #'s
50,75,100,etc.this is your yard edge sight it in at 75 yrd's and if what your shooting at is 100 yards just turn the knob to the correct setting.good luck Read More At : Bausch & Lomb Hunting Elite 4200 Riflescopes Matte Finish......