Welcome! All depends on which direction you want to go with the tanks, ie fish only, coral (and then which types) , mixed reef etc...
Do you have any one particular fish that interests you? If not yet, research fish and try to find that one 'must have' fish and then research what they can and can't get along with and round out your livestock from there. Compatibility is a big factor in this hobby. And if you want to get into coral that adds another level on what kind of fish you can keep (reef safe fish).
