Flip open the quick release.
Pull the cam down, so it does not touch the tank stud.
Loosen wing nut (the wheel should be able to spin freely at this point).
Put one foot on the back of the deck while leaning to the rear. Apply about 75lbs. Pressure with your foot.
While keeping weight at the back of the deck, lean over the rear, pull the purple cam back up, so it touches the tank stud.
close the quick release back and forth, while tightening the wing nut, until it feels nice and tight.
Once it is tight, take it for a spin. If there feels as if there is some slipping, repeat the steps.