A Flow at it's minimum UI level is a React function component.
This component can be anything, the minimum code to implement :
A Flow is an interface element that will basically store it's data to the Program and generate appropriate code.
It's then recommended to :
deserializemethods to store and load Flow data.
onCodemethod that will generate code specific logic when executing the Flow on it's Client.
onDeletemethod to pop the Flow on the current Rail.