How to Enable Touch Scrolling - Windows 10

Using my laptop in tablet mode, I can only scroll by tapping the scroll bar in certain place. This gives me a partial page down down effect rather than a smooth scroll. Touching anywhere else brings up my keyboard. I have no "preferences" options to change this. It's super annoying when I have hours of reading. 

How can I switch to smooth scroll? I am using Windows 10 with a Lenovo Flex, pdf version of the text.

Thanks