I have no experience of these devices however I had a wee look on google and found a couple of things that might help.
[fire tv silk browser scrolling]
https://www.amazonforum.com/forums/d...crolling-issue
https://www.amazonforum.com/forums/d...-fire-stick#c8
"You have to hold down the big circle button in the middle of the firestick remote (the one you select things with) and while holding that down use the circular arrow things (that surrounds the big button) to move up or down. Your dragging instead of scrolling so I believe up is down and vice versa"
"Found it! I found out how to "grab and scroll" on the Craftsy video that I was viewing. My issue is resolved.
I clicked the select feature. I pushed the down portion of the button because I was trying to scroll down. That is why I was unsuccessful. I went to the very bottom of where I was trying to scroll, grabbed the page and scrolled up so that it brought the part that I was trying to see into view."