How should parents talk about "sex education" with their children

Children nowadays are not easy to manage. Contact with things is becoming more and more open. As parents, it's better to talk about this kind of problem with children without being secretive and serious, just like talking about family. I think it is more difficult to control children's own curiosity and prevent them from touching bad things. The landlord can start from the physiological aspect and talk about the difference between men and women. Then tell him what their psychology will be like at this stage, which are normal and which should be avoided. This is a big project. Wow.