It is really easy on this machine, you don't need to lift the rear end up if you dont want to, but I am sure it tells you how to do it in the manual. Did you download the free on from this site? Anyway, there is a nut/bolt combo on the very back which holds the rear sprocket and brake assembly that goes right into the frame of the machine, and on the insides you will see 2 cams with numbers on them. Loosen the nut/bold, and just move the cams accordingly until you get the right amount of slack on the chain. Just be sure the cams are lined up with each other, which is indicated by numbers. Then just tighten the nut/bolt back up. Very simple to do. You should read the 13t how to do it thread, they may have better detail and whatnot in there, along w/ the easiest way to change the front sprocket.