Here in this Document, I tried to explain the steps involved in Procure to Pay Cycle. This is a pure functional Stuff and helps you to understand the navigation steps. I tried to keep as simple as Possible for clear understanding. The screenshots given below are taken from R12.1.1 apps instance.
Procure to pay cycle in r12 with screen shots 2011-03-23
Procure to pay cycle in r12 with screen shots