You can use either Hover Touch Mode or Mirror Touch Mode in the NextD Remote app on your smartphone:
In Hover Touch Mode, there are 3 ways to swipe and scroll on the TV screen.
1. Put 2 fingers together to swipe (this is similar to how Macbook and Windows 10 laptop touchpad works)
2. Double tap then swipe (this is similar to how PC laptop touchpad works)
3. Long press then swipe
In Mirror Touch Mode, use a single finger to swipe.