Hi John,
You can have several options for displaying PDF scores - scrolling down/up, 1 page per screen, 2 pages per screen, half-pages per screen - it all depends on the software used.
Below is a link to a document explaining my setup with a Dell laptop/tablet 2-in-1. And the way I've arranged it to display scores automatically on selecting a registration (Tyros 4 keyboard).
My personal preference is for displaying 1 page at a time - I move forward and backwards through the score a page at at time using a PageFlip Firefly Bluetooth/USB Pedal. The pedal can be configured to respond to a range of 'keystrokes' such as Page Forward/Back, Page Up/Down, or customized to anything the PDF viewing program understands.
There are now quite a few solutions around for Apple IOS, Windows and Android platforms including Songbook, Michael Bedesem's OpenText, MobileSheets, and if you just need display then any PDF Viewer such as Adobe Acrobat Reader, Foxit, Sumatra, and Jørgen Sørensen's
Music Book Viewer Regards,
Phil
Organisizing and Displaying Sheet Music