What you do during the day is totally up to you, the crew and your skipper. Each day will vary, depending on the itinerary. You normally spend your day chilling on the yacht sailing from one port to another with a stop in a bay to cook lunch and have a swim. There will be a The Yacht Week party or event each day too, perhaps a circle raft or a party/activity once you arrive at the next island. You will have time to explore the each island too and try the cuisine at the local restaurants.
The distance between ports varies, but you would normally expect to leave the marina early/mid morning and arrive to the next stop in the afternoon. Of course, it also depends how long you spend having lunch and relaxing in bays and swimming.