Well, to start with you'd need singificant rank and training in one or more styles of taekwondo. You need an affiliation with some organzation for promotions, unless you're sufficiently highly trained and ranked to do your own org. You'd need a place to teach. You'd need prospective students. You'd need equipment (heavy bags, kicking shields, targets, etc) and money for startup costs.
Do you have all those things?
And welcome to MT. If I were you, I'd go to the Meet & Greet forum and tell us something about yourself.