Hello, I'm B and I teach whatever. I studied whatever at wherever and decided to become a teacher because I whatever.
It's kind of like writing a CV but more personal and personable, almost like having a conversation with someone you've just met.
Fairly high up it would be good to say why you became a teacher, what it and your students mean to you.
As a parent who highly values education, I would hope -- expect even -- to see considerable enthusiasm and passion about your work.