Take photo of the entire thing + the wiring before you touch anything .
Basically it is the 4 mounting bolts + the PTO bolt .
If there are spacers between the pulleys lay them ( & the pulleys ) out on the ground and photograph them as well .
Most drive pulleys are symetrical but some are not so the belt can foul if installed upside down .
yep, camera's are your friend. Take multiple photos from different angles. You'll be amazed how easy it is to take a photo and something like a shadow etc., blocks exactly what you need to know to put it back together.