With all seriousness as they say there are no stupid questions. At least you asked. My Son and I inherited a small salt water tank off a so called friend ( my first ). It is 4o gallon. It was infested with hair algae because all this guy did was dose it for balance, and little else. Also gave us 2 very problemed aggressive fish. Since I did aquariums for 60 plus years I know the 2 golden rules. Do not overstock, and do not overfeed. It took me several months to straighten the tank out. I run a canister filter, and a hang off the back skimmer with a " Razor " led light. Total investment about $ 2000. My new 90 gallon all set up including a sump under it about$10,000. Everything totally necessary. I will assume you are not in that monetary position. So again glad you asked. First I would sell the tang which are always in demand. Never deal with that person in the store ever again. Start your education. Bulk Reef Supply has a series of excellent videos from start to finish, but you can keep it very simple at first. Stick with hardy or smaller fish, and simple coral. Mine are mushrooms. They are very colorful, and will breed for you. When you see my pictures remember they all started from one of each. Also a lot of articles on this site to read from some very highly qualified people ( more than me for sure ). Would not want to see you make the same mistakes that we all have.