This book by Alison Noice https://www.bloomsbury.com/uk/day-skipper-for-sail-and-power-9781472944818/ will tell you all you need to know, and it is written in a very understandable manner, with different senario's for both the fast powerboat, displacement powerboat, and WAFI.
A relative (not saying who) did the PB2 and gave me a very nice compliment ......... he said he had learnt very much more being out with me, than he did on the course, and the instructor was very surprised at his close quarters handling ability, but, at least he now has a piece of paper (ICC) that allows him to drive and rent a boat in mainland EU. The only issue he had with the instructor was Colregs ........... he was told to power on through as he had the right of way, but instead he adopted what I had taught him .......... unless you are 100% sure of another vessels intentions, then avoid like the plague !, especially at speed.
I really should do PB2, I know all the local instructors, and we see and chat to each other all the time when going in and out of the estuary harbour, so I guess it could be quite fun.
Brother in law (James) who often crews with me has 'Ocean Yachtmaster' qualifications which he took many years ago when living in Oz.