Your temperature should be 74 (lowest) to 82 (highest.) I would stay away from damsels as they become very aggressive and territorial. If you want to add fish later, the damsel may take exception and attack new fish.
You can start with a yellow tang if your tank is 55 gallons or bigger. False percula clownfish is also a good fish to start with. Many people do recommend damsels while you are cycling your tank, but if you are going that route, please remove them before adding your more valuable fish.