I want to save some PDFs (Solutions to my workbook so nothing illegal or smth) on a page I can access but there seems to be some kind of authentication in accessing them coz the requests have stuff like signature that change every time

When I go to that link I get a 403 Error. As the file gets loaded on my browser I think there must be a way to access it. The page uses Mozilla's pdf.js if that helps.

Thanks in Advance