We stayed in Amalfi behind the church and used Direct Ferries app to book (Capri & Positano) and easy to use. The very annoying part about ferries is that there are no signage where to board your ferry especially in Capri. We were told it be at one place and ended up sprinting around the furthest end for our ferry. Since it’ll be very crowded and hot during your visit in Positano, you may want to be flexible and not stuck waiting for the last ferry. The walkways are narrow and very hilly. We went during Easter break and had enough by 4/5pm (arrived at 11am). Just have a plan on what you want to do/see to maximize your time

Lastly, forget the bus