Hello and
WELCOME To The Boards !!!
The most important item you need right now is information on salt water reef systems. I can not over emphasize this enough. While the net (other than the forums) is great for something very specific, it does rather poorly at providing background information that is required for salt water systems. Which is what brought you here.
What you want to do is to obtaining several good books on state of the are salt water reef systems. Two excellent ones to start with are
The New Marine Aquarium by Michael S. Paletta and
The Conscientious Marine Aquarist by Robert M. Fenner.
At this point you need good, solid, basic information. Read, study, and understand the material, and at that point you'll be able to ask any questions you may have on anything read and you will also have a much better chance with first time success.
My second biggest suggestion would be to purchase decent equipment from the get-go.
I highly suggest you to purchase an RO/DI water filter. At a minimum, it should have a pressure gauge, vertical DI resin canister and a Filmtec RO membrane which makes 75gpd at 98% rejection. It should have a high quality carbon filter, not granular activated carbon. In other words, stay away from ebay. Buckeye field supply, air water ice, the filter guys, or cultivated coral are where you should shop for this. Water is the most important ingredient;
The next piece of equipment I suggest you should invest in is a refractometer. This allows you to properly check the salinity of the water you make.
You will need salt of course. Water changes are an important part of filtration for a successful reef tank. The usual rule of thumb is 10% - 20% every two weeks. You can tailor this to your needs or the needs of your tank. High quality salt is much easier to work with than low quality stuff which is usually lacking in many elements in their proper portions.
Take your time, go slow, read some books, ask questions, ask more questions.
Once you have the basics down, your next step will be to figure out want you want to keep. This will govern the more advanced equipment selections to some extent.
You may also want to check out this thread here on aquarium forum -
http://www.aquariumforum.com/f18/basic-marine-fish-keeping-360.html
This thread will help cover the basics in a little more detail. It also goes on to more equipment such as lighting, water circulation, protein skimming, etc...
Again Welcome to Aquarium Forum and more members will chime in as they come on the site.