Please try this:
Click on the Start orb/button, then click upon All Programs, then click in the HP folder. (If the HP folder is not present, stop there and let me know - you will need to install HP software for your printer, which is available free online. I will advise you further in that case.)
The click on the 'HP Photosmart 5520' folder (or a similar name.)
(Again, if that is not present, stop there and let me know.)
HP Scan will be found within the above folder (if HP software for your printer has been properly installed.)
In the HP Scan window, you can select 'Scan To PDF'... scan a page by (selecting options, then) clicking on Scan... be sure to enable Scan Preview
, or you will be unable to save a multi-page original into a single file.
When the scan of the first page completes, click on the
(+ sign button) on the left side of the HP Scan window, to scan additional pages.
Once all the pages are scanned, click on Save or on Done to end the scanning/capture the pages.
And if you don't have HP Scan software on your computer yet, then please go to
Start - Control Panel - System Information,
and look for the 'System Type' information, which should read either 32-bit or 64-bit. Reply telling me which of those two your Windows type is, and I will advise you as to how to obtain and install the HP Scan software.
I hope this provides you with the answer you need to your question in every respect. If so, please rate my Answer, or else reply informing me what rating you wish applied. Thanks.
(If any other info is needed to make the answer complete, please reply and I will try to provide it.)