Email Parser connects the different email processing steps with arrows. When an email is received, it will follow the arrows starting from the source of the email. It will run any filter, parser, or action found in the path. There can be even bifurcations and loops.
An arrow also shows the connection between two fields. In the image below, the arrow that goes from the field “Subject” to “order_id” means that “order_id” is captured from the text contained in “Subject”.