Can someone help me with a belt diagram for a snapper mower model number lt12d41 its an older mower prob 10years+ 12hp

I have a "yard Machine" riding mower from Wal-mart. It has 3 pullys that hold the belt on which in turn moves the blades when engaged. It came off, and I cannot get it to fit around all 3 pullys again? What am I doing wrong? [email protected] When I disengage the it gives me more slack but will not go on!