Forget about yellow tail damsel. Very territorial and aggressive fish. They don't play nice with others. Most fish stores won't even take them back.
Before adding fish you will need to cycle your tank. If everything is new, sand, base rock etc, it will take about 6 weeks to complete the cycle. Adding a cup of sand from your LFS
will speed the process a bit. The more live rock you add the quicker the cycle as well. But it will cost you $.
Make sure you bottom rock sit on the tank glass bottom or better yet egg crate. Then add sand Otherwise burrowing fish/shrimp etc will undermine the rock and may cause a collapse.