Welcome to the forum, tons of very friendly, experienced people on here so you are in good company. Starting an aquarium, especially a saltwater aquarium is like going back to high school or even college science classes, in the beginning there are several tests that are required Ammonia, Nitrite, Nitrate, just for the cycle phase. Once you are past the cycle USUALLY nobody really checks ammonia or nitrite unless something major has happened. But then a whole new group of tests come like phosphate, calcium, magnesium ect. Depending on how deep you want to get into this hobby i.e.. time, money, and research will help you decide what type of setup you really want, be it a FOWLR, LPS, SPS or mixed. Again welcome and just remember "the only stupid question is the one that is never asked"
B.T.W, if you do go all in sometimes reefing feels like this.