Tis tres simple
a. Find the range your rifle is best at, say 30 yards.
b. pick a magnification for that range, i recommend 4x
c. draw a cross on a piece of A4
d. 10 rounds, at the crosses center, all your shots should land in a group, say top right.
e. use the vertical and horizontal dials say 10 clicks each to bring the crosshairs closer to your grouping
f. repeat, 10 rounds and repeat again until you have a perfect zero
from my experience with my old AAs400 (air rifle) that's my quickest way of doing it.
if you do want a hand though, bring it to the next game