Italy itinerary advice needed

Hi, my girlfriend and I are planning to visit amalfi coast but extremely confused about the itinerary. To start with should we stay in sorrento, positano or amalfi - which is more convenient if we want to move around and visit all these places? Secondly for how long should we plan the trip, please feel to drop in any suggestions or recommendations

We are both 23 and want to explore the island and visit nice restaurant and bars