There are lots of method books out there, teaching different methods of playing the harp. But you can’t learn technique with a method book alone. You need a teacher who can explain the method and guide you. I’ve never taught video lessons, but that seems to be quite popular. Given that you are having such a hard time finding a teacher, I would suggest you try video lessons with someone. You should start by lining up a teacher first to teach you, using some sort of video hookup, and then let the teacher suggest the book you should use.