Help copying single file format

[gary1854]

Please help!
I have read the tutorial thoroughly on similar to what I want to achieve the tutorial where it shows you how to use rules to exclude all file types except image formats only I am trying to achieve the same but only for PDF format, I want to scan a whole site and only down PDF files From it It.  I am clearly doing something wrong using the rules feature only instead of using the image formats using my PDF format. It will ignore everything and download absolutely nothing at all, but I know that sees the files because if I don't use any rules at all until it to scan a site I can come back 12 hours later. It will still be scanning the site and will have already downloaded well over 1500 PDF files again all the PDF files all the files and everything else that's coming along with it and bloating my drive please someone is there a video on that tutorial where I could see it. I've tried looking through YouTube. I can't find anything if anyone can show me in a video of how exactly they're achieving this please let me know. Thank you. PS I have also tried not using rules and using the content type application/PDF and it doesn't find any PDF files but again I use no rules no exceptions. Nothing just the site all the PDF files just fine.