Hi
Well my first suggestion would be to buy a book, The Conscientious Marine Aquarist, is a very good one.
After you have read that book then you can think about getting started.
Is a 30gallon the biggest you can get? I honestly would recommend a tank size like a 58 or a 65 gallon if you need to start out small, 30gal is a bit smaller than I recommend but is doable if you are very committed.
Start out by buying your tank and stand, put the stand where you want it and level it with a level, use shims to get it level, then fill the tank with tap water and check the level again and be sure tank isn't leaking, put your pumps and filters on the tank and run them to be sure everything is working properly. If everything is fine, then drain the tap water completely out fo the tank.
Either buy an RO/DI unit or buy it from a LFS, Fill the tank with the RO/DI water, mix your salt in the water first, after the water is the correct salinity (35ppt on a refractometer, or 1.025 if you are keeping corals and inverts and fish, 1.022 if you are keeping fish only).
Start up your pumps and heater, filter.
Add the sand and uncured LR, lights are not necessary right now IMO, skimmer is. Things will be cloudy for a while from the sand, this is normal, Once the tank is cleared up , start testing your water, you should see a spike in Ammonia, then a spike in Nitrite, then a drop in Ammonia, a rise in Nitrates then a drop in Nitrite, then a drip in Nitrates, once nitrates stop falling (usually around 30), you can do a 20% water change check levels again after a week and then add your cleanup crew. Do not worry about levels other than Ammonia, Nitrite, Nitrate during the cycle.
Lighting: this depends on what you want to keep, if you want only Fish then a simple two bulb flourescent fixture with one 10k bulb and one actinic bulb will be fine, if you want reef we can talk about that later.
Hope that helps a little.