Difference from the other components
The main difference between the FlowComponent, and the Scroll- and PageComponents, is that its content is dynamic.
With a Scroll- or PageComponent, you add layers or pages, and that content is then scrollable or pageable. Done.
But with a FlowComponent, you add and remove screens on the fly. When you transition to a new screen, the component will grab that layer and change its place in the hierarchy. (In the Layer Panel you can witness how the layers are reordered.)
That is why it’s best to setup your FlowComponent at the end of your project, after you’ve created the screens, pop-ups, and other content you want to show in it.