With my limited knowledge I will give my best answer!
Someone with more knowledge than I have will be along shortly!
Shoot your rifle at 100 yrds.
If it hits 2" higher than the POA (Point of Aim),
Then turn the knob 8 clicks. (8x1/4" = 2")
If you want it sighted in at 50 yrds, just do the above at that distance.
Best of luck!