383 Mower deck help

I recently picked up a Cub Cadet 383 at auction. I am trying to get the mower deck attached. I found a pdf of the manual online but the photos are illegible.
This is supposed to be the same as a 76, 80, 81, 182, 282, 382.

From what I can tell there is supposed to be an idler pulley where the belt wraps arround the engine pulley. There is something there but it is not on the same plane as the belt. Nor does it change position as I move the PTO lever.

A picture or clue would be appreciated