[Someone?]

Trick is(the Easy way, 2 people) have some hold down the bottom tension pulley with a short socket and long ratchet (add tube or something if you don't have a 12 to 14 ratchet) get the belt on top of the socket that way you can use Both Hands to pull up the belt over the Grove less bottom tension pulley it will be quick.

PS that's how it works on the late 08 and up Double belt set up and Ive never seen a single belt set up but you will still need to pull it over a Grove Less tension pulley.