Buy the RO unit or RO/DI unit to make it, or some stores carry the water. Right now I'm looking to buy the unit because I plan on doing more tanks SW, however with a small setup I'd just go buy the water. Well since your doing FOWLR, lighting isn't important, however I'm guessing you have a 24 watt or if it's the deluxe 2x24, (of which the single might be able to keep some lowlights if you go that route, currently I am keeping some of the easier soft corals, but I have the deluxe, however none of that is important right now)
To set up your tank, what I would do if I were you is get the water, than mix the salt and the water (in the tank is fine since there will be no live stock at first), then turn on the pump wait like a day or two until the salt mixes well, measure the level and make sure it's fine. Then I'd just add the live rock and sand or crushed coral, and then use the test kit to determine how far along in the cycle you are, of which the die off helps of some of the stuff on the LR helps cause it. There are other ways to cycle, and speed up cycles, but you can just check the stickies at the top. Almost forgot media, but as far as media, there a variety that you can use, so the choice is yours. Myself, I have the foam in chamber one, chucked the bioballs after reading about the negatives and did LR rubble in chamber two, and then I have the pump and heater in 3. Most likely I will be adding cheato and getting rid of the sponge though in the near future, as well as some other mods in order to increase the flow.
In terms of LR, a pound-1.5 or even more if you want, per gallon is good.
