Action Nodes
Action nodes are the building blocks of Actionflows, they are represented as a circle with an icon. They perform specific tasks, e.g. updating data, performing calculations, and API integrations, and are joined together using connectors.
Action nodes can be dragged from the toolbar onto the canvas to create a new action, and some can be clicked to see existing objects, e.g. click 
Open Screen to list existing screens, then drag from the Repository onto the canvas.
Most nodes run once per record they receive from the input connection point. However, some nodes only trigger once after receiving the final record or once per flow, e.g. Open Screen, 
Start Phase and 
Open URL nodes.
Attributes are mapped into action nodes as Input Parameters and out of action nodes as Output Attributes. Connectors between the action nodes then pass through the data and attributes. Every attribute is passed through* but in order to use an attribute in a specific action node it must be mapped in to it as an input parameter.
*although there can be exceptions, such as the Converge action.
Once mappings are configured they will reused in all instances of the Actionflow. This is because the action nodes sit within the Actionflow itself and only the data coming into and out of an Actionflow changes for each instance.
Note: The specifics of mappings and connectors are covered in a later in this course.
