The phrase "to scan the page" means to quickly look over or read through a document or webpage without reading every word or detail, usually to find specific information or get a general idea of what the page is about. Full definition
If you get to a question you don't know the answer to, just go to your screen shots and find the answer by quickly scanning the page for the info you need. (drive-safely.net)
A further point about textbooks is that students often need to quickly scan pages. (goodereader.com)
I don't want to take the time to scan them page by page though... That's for the birds and would cost way more than $ 50! (goodereader.com)