The hardest part is you need to keep stable water parameters, corals can die from a lot smaller changes that fish wouldn't mind. You probably want to make sure you have a pure water supply, don't want treated tap water in a reef tank.
My suggestion, as someone who plans to do a SW
tropical reef sometime in the future, start with a 29g reef ready tank, FOWLR
, (fish only with live rock) and when you feel you have control of what you're doing and everything is stable enough, upgrade your lights and start adding corals. The key will be research. You'll want to get only reef friendly fish, and make sure you don't get corals that will fight each other. Also, you'll want higher level light when you switch to coral, if you use too much light without corals you might start algae blooms.