Funny I just adjusted the auger belt on my Ariens, and yes you are correct the manual is confusing. Adjustment is extremely simple. Remove the metal cover over the belt, there are four bolts to do this. Loosen the nut on the center of the idler pulley for the auger belt, I seem to recall it takes a 13mm wrench or so. Then you push the idler inward to tighten the belt enough so that when you pull up on the handle there is no slippage of the belt around the idler pulley. Tighten the nut on the idler pulley, replace cover, have a beer.