Help my thick afro hair?

Hi I have very thick dry coarse frizzy afro hair that I have severley dried out and damaged with chemicals etc. I Dont know what todo now with it and I everyone one at school picks on me. What products should I use? What are they called? Its really dry and its all frazzled, I live in scotland and I have never been to a hairdressers, what do I do ? where do I learn how to deal with my afro.