How did you explain to your child about first crushes/puberty?

[Mustafa16]

No one had this talk with me as a child because I had liberal parents (at first, my father later became more religious), or because my father was distant and my mother was busy, or both. My father eventually had the "sex talk" with me when I was 13, but I started puberty and had my first feelings of lust at age 10, and it didnt seem like the talk helped because he didn't really explain the need for gender segregation as far as I can remember, or about some other key elements I hear Muslims talk about. Out of curiosity, what is the Islamic way of telling a child about gender segregation, the need for modesty, and puberty, etc.?