HELP! - Scrolling Behavior Question

MOBILE and Desktop: I am trying to figure of how to get a widget (arrow) to appear when the user has scrolls (horizontal) in a list of items (menu style) can someone provide some insight or help? Its more advanced than just using the show/hide. I want to be able to set a specific value. Maybe I am using the ScrollX and Variable event incorrectly.

Thanks!!

What do you mean by “set a specific value”?