It ain't hard. Take off 5 8 mm bolts that hold on the front sprocket cover. Flaten out the washer that secures the nut on one side. A 27mm/1 1/16in socket (preferably six-point) will get off the big nut with the aid of a breaker bar or cheater. Put it in gear and have some hold the rear brake or put a padded bar though the wheel and on top of the swing arm to keep the wheel from turning. You will have to loosen the rear axle nut and loosen the chain adjustment to get the sprocket off. When you get the sprocket off clean out all the crap that has accumulated in there. Put the new spocket on and tighten the big nut to 94 ft/lbs. Bend the washer over. Adjust the chain and retighten the rear axle nut.