Welcome to the boards
There is alot of good useful information on here. Do alot of reading before you start, use the search to answer your questions before you post, and dont always take the first piece of advice that someone offers. And everyone will give you one good piece of info......Take it slow, dont rush. A heater may not be necessary, depends on where you live. If you want to upgrade your lights, then a chiller might come in handy. To start, mix your salt & fill the tank add your sand and whatever rock you like (live or base). You might want to use live rock to cycle, most use a piece of shrimp (raw, frozen from the grocery store, alot faster than rock) Your tank will go through its cycle Ammonia spike followed by a nitrite spike, then to the nitrates. When you get to the nitrates, your cycle is complete. It is necessary to do small water changes once your cycle begins. You cannot add any life until this cycle is complete. This is the 5 second lesson.....Im sure im forgetting stuff, but I have to put the little one to bed. GOOD LUCK!!