HI Bilsky ... you can't scan multiple pages at once unless you have a scanner that has a feeder. If using the glass you have to replace each page one at a time which means it will scan them one at a time.
Below is a support forum from HP that might help.
https://h30434.www3.hp.com/t5/Printers-Archive-...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.