Hello, This Lesson has another problem, I think, https://learn.arcgis.com/en/projects/oversee-snowplows-in-real-time/
If you scroll down to Add Elements (Under Create a dashboard), When you use the List as an element and you selected a layer Vehicles (Latest).
On my side, if you go to Number 6 . This is about Actions. When you add an Action, There is a list you choose from. On my side, I only have a few list to choose and one of them did not appear Follow Feature
Here is my screenshot of what I am talking about

I am, I think, maybe this layer is not connected to this ArcGIS GeoEvent Server, which cause not to display the follow Feature ?