Volunteering in a school

I a relatively new to Zihua and am interested in working in (not donating to) a school. I am a retired teacher in the U.S. and would like to help out in some capacity in which I am working directly with children. I haven't seen anything about volunteer opportunities in schools except for fund raising. I speak Spanish at a very basic level but usually can get myself understood. Does anyone know of a school or some other organization that can use a hand working with children? Thank you.