The basics of every marine system should be a deep aragonite sand bed, live rock, and a protein skimmer. Your situation is simple, because you don't have as many options.
For a sand bed, I suggest 4''-5'' of aragonite sand. This depth will allow for proper denitrification. Anything less can cause problems by trapping nutrients and eventually leading to algae blooms.
For the live rock, you want between 1 pound and 2 pounds per gallon, depending on the density of the live rock. I suggest looking at pictures of completed reef tanks to judge how much rock to use. You should also post pictures of your progress as you go along, so that we can offer our input.
For a protein skimmer, I would suggest the Berlin X2 Turbo Skimmer. The skimmer is the most important purchase you will make, so you want a high quality unit. Here is where I personally order my supplies:
Berlin X2 Turbo Skimmer - 13.7 in. x 20 in. x 7.9 in. | Venturi Models | Protein Skimmers | Aquarium - ThatPetPlace.com
Then you have the basics. You need a submersible heater, salt mix, a hydrometer, a couple of power heads for water flow, and your lighting fixture. Lights depend on livestock, so I can't make a recommendation yet.
I would personally recommend a UV Sterilizer on your display. You can order one from the same web site as above, at a very reasonable cost. A UV goes a long way to helping prevent the spread of disease from one animal to the next.
Next you need to decide where to set up and what size quarantine tank. I would recommend a 20 gallon quarantine tank, but a 10 gallon is sufficient. It can be run bare bottom, with a simple sponge filter and air pump. This will look very similar to a freshwater breeder or fry tank.
Finally, you need to order your testing equipment and chemicals. You need tests for Ammonia, Nitrite, Nitrate, pH, alkalinity, and calcium, at a bare minimum. Many people would tell you to also test for phosphate and magnesium. You will need the correct chemicals to adjust your readings. You need an alkalinity buffer. I use Kent Marine SuperBuffer DKH. You also need a calcium additive, such as Kent Marines liquid calcium. Some hobbyists also use a 2 part balanced buffering product, such as B-Ionic.
There you have it. The basics. You will probably need to start several different threads discussing the why and how of each. Honestly, this discussion normally comes in hardback form, and is about a 500 page read.-)