Vaitape is the arrival point of the ferry from the airport, and is the only "town" of any size of the island. At the southern tip of the main island, Matira is the location of the largest beach as well as several hotels and restaurants. The central part of the island is extremely mountaineous, tough to access and not inhabited and furthermore devoid of roads of any kind.
The way you get around in Bora Bora depends greatly on your accommodation and its location. Several resorts are actually located on motus and not on the main island, hence the need of boat transportation to get anywhere. Boat transfers from those motus resorts to the main island or between the resorts and the airport are usually provided. Accommodations located on the island generally also provide a transfer to and the Airport ferry quay.
On the main island, there is only one sealed road. Public transport on the island is limited, consisting of a single bus that goes halfway around the island and back approximately every hour. Taxis are also available.
Operators of activities and restaurants sometimes but not always provide a transfer to and from the accommodations - be sure to ask when booking.
Renting a bicycle or a small buggy can be an option if you plan to have your freedom on the main island, but the road is sometimes very narrow, and in bad shape.