belt broken and idler pulley off

Dryer belt broken, when opened to remove also found idler pulley on bottom of dryer. How do I reattach or do I need to buy a new one. First timer at dryer repair. Thanks

The idler pulley sets in a slot on the base on the right side with the wheel part facing the drum.

Here’s a breakdown which should help. http://www.appliancepartspros.com/partsearch/model.aspx?model_id=246898

Nat

I would replace the motherboard AP4436216