Are you talking about a preschool? That is more of a daycare center for younger toddlers (like ages 1-2 or whatever) and not an educational institution, hence the laws against any kind of teaching. They are only allowed to hire caretakers, not teachers.
@Bilinguistas is asking about teaching young children who are kindergarten-aged, so she is either asking about teaching at a kindergarten or an after-school “cram school”, or teaching as a licensed private tutor. She has not clarified yet.