If you read the blog post, they don't provide help or guidance for regular bookworms on how to scan. No information about what they expect.

Also, flatbed scanning a whole book takes many hours. It's one page at a time, line up each page, press the book flat and scan, for hundreds of pages.

You'd likely need to buy, or have access to a book scanner. Which is fine, there are cheap models, but who knows if that would work for them? They don't say. It doesn't seem like they're expecting help from you or me.