Buy tank, lights, poweheads, heater, salt, RO water, hydrometer, test kit, and sand. Fill the tank 2/3 of the way with RO water and mix in the right amount of salt. Put in the heater to warmi it up and put in the powerheads to help mix the salt. Wait a day or two to make sure it's all dissolved, then add live rock and sand. Fill the tnak the rest of the way with pre-mixed saltwater. Test for ammonia nitrites and nitrates to keep track of the cycle. Don't forget to keep adding RO water for evaporation. Once it's cycled, add clean up crew (snails, crabs, etc) to help with the algae, then add fish. One or two fish at a time. Then you can add corals and whatever else you want. You could also add a skimmer and a sump and a ton of other equiptment, but you don't have to. This is how I set up my 37g. Others will do it differently. There isn't really a 'right' way to do it (but there are 'wrong' ways imo). For more info try reading the pinned topics.
