sounds like you got grasp on it for sure just a couple of suggestions either buy new sand or rinse about 200 times and if your going to add sand first then make sure your rock touches the glass on the bottom i would personally go with new sand though.no light needed for cycling and watch your phosphates and nitrates as they are hard to get rid of when they are high but easy to control when the tank is new
cheers mate and welcome to the salty world any q's just fire away