You'll be wanting a 6ft long tank for a regal tang. Most tangs are open water swimmers and need such a long length to live healthy.
You'll want to make sure you have intense lighting to support an anemone, the taotronic LEDs are the cheapest way of doing this.
There are several fish that will do better in groups.
You will want to get yourself a sump and a good protein skimmer so you can keep your water as pristine as possible for an anemone. An ro
unit is also in the running, unless you can buy it at your LFS
Live rock is live that has become live after you cycle your tank. When you buy live rock, you are buying rock that was once live and can be full of all kinds of critters.
Do not put sea shells from the ocean in your tank. They can contain all kinds of nasty stuff as they are normally collected from beaches or in tidal zones, where the pollutants will be most potent and can be easily detrimental to a closed system.