There are many many dive shops and resorts on the island. you can make research on HK's dive shops for information.
You may better stay at the middle of the beach because you can visit the whole beach. If you stay at one end of the beach, you may need to hire tricycle for transportation.
There are hundreds of resturant and bar at the side of beach. Evening is beatiful, people are kind, resort are OK. Enjoy your trip.