The belt broke in our dryer and we cannot figure out how the new belt goes around the drum - too much play left. There is the piece attached to the motor which the belt sets on and then there is a pulley - think maybe there is something I’m missing putting the belt around that.
The belt goes around the drum, grooves toward the drum, pull the belt together at the bottom, put the loop that is formed through the Idler pulley and around the motor shaft. (you will have to push or pull the idler assy. toward the motor(against the spring pressure)
There is a good STICKY at the start of this forum
http://forum.appliancepartspros.com/dryer-repair/25860-dryer-belt-diagrams.html