It seems that you can't buy documents for the blind from the internet, and it seems that Braille publishing houses also sell braille textbooks in clear text. I don't know why you bought blind documents. As far as I know, blind documents are inconvenient, bulky and lack of resources. It is inconvenient to carry. If you want to learn Braille, you can buy China Braille, and there are related tutorials online. Good luck! By the way, for your reference, a Braille digital library has been opened online, which seems to be specially designed for blind friends. All kinds of books in it are comprehensive! Have a look sometime! Very good! !