Entities are variables that can be extracted from the user input.
The entity component is used to configure how the entity is going to be extracted and validated.
The entity name is important because it will be used as a key when saving the extracted entity in the user's session.
The entity type defines the format and rules a valid entity must match. There are some system types supported out of the box, such as Date, Number and Free text and you can define your own custom types. Read more about creating new Entity Types.
When the flow reaches an Entity node it will first check the user's session to see if he doesn't already have the entity in the session. If he does the flow continues, otherwise the agent will send the prompt message. The prompt message can be configured in a similar manner as a regular Message:Messages.