First off, welcome to the boards. Everyone will be happy to help you out, but you need to help us out too. If you can be more specific on what answers you are needing, and possibly post pictures of everything you have already bought, or even just a list that would be a start.
I'll try to give you some simple tips to help you out...
1. Buy an RO/DI unit to make your water. This will be a worthwhile investment and probably one of the most important purchases you will make. Dont try to use tapwater, it will just cause you problems down the road.
2. You need to decide if you want to keep corals or fish only... I'm sure you'll want to eventually buy at least some soft corals, so buy a good salt from the get go.
3. If you seriously want to get into corals, good lighting is essential.
4. If you just have a simple hang on back filter, you should probably look into getting a protein skimmer and some additional powerheads for flow. Proper flow is very essential! A sump is an option as well.
5. Get your tank set up with a sand substrate and 1-1.5 lbs of live rock per gallon. So thats 40-50 lbs in your case.
6. Allow the tank to cycle, go slow and remember - GO SLOW! Rushing the process of adding fish and corals too soon will only make your wallet mad in the long run.
Im sure I've left something out, or someone may have another opinion on the matter, but I hope this gives you a general idea anyway. Dont forget the "search" feature this site has. It is an invaluable tool - everyone started where you are right now and you will find that most of your questions have already been asked time and time again... Keep us posted!