slow down and take a breath. this is going to take a few weeks. Patience is the most important part right now. First off, no matter what we say, you will most likely re-arrange the rocks about a dozen times before the end of the week. Keep them how they are for now, they look just great.
Your salinity is within normal limits. leave it alone for now.
use a piece of shrimp from the market. some people try to put in a damsel to get things going, calling it a sacrificial fish, but I am not a fan of that for one reason: what if it lives? there is NO WAY with that tank you will EVER catch the damsel. they tend to be SUPER territorial and will hassel and even kill other fish that you put in after it so don't use that method. a piece of shrimp is all you need.
As for testing the water, you won't need to for a while. Once you drop in the shrimp leave your tank alone for about a week. don't even touch it. test after a week and if the ammonia is still present, leave it alone again, for another week. keep testing it weekly until there is no ammonia or nitrites present in your water, then do a water change to reduce nitrates and you are good to start one fish. that process will take between 3-4 weeks. Patience young Skywalker, patience...
-Doc