How to understand the "flows" at ASM?

A flow defines the access path leading from one URL to another URL within a web application. For example, a primary web page may include a graphic and a hyperlink to a secondary page in a given application. From a configuration standpoint, the flow is a data structure model representing web application components, such as URLs and parameters, and the interaction between them. The flow contains all of the data necessary for evaluating the information in an HTTP transaction. Flow data includes the referrer object, HTTP method, schema, requested object, and any parameters that the administrator wishes to include in ASM processing. Flow control offers an extremely robust, granular level of security for a web application by enforcing a sequence of permitted transactions. You can configure protection for specific URLs and specific parameter/value pairs of objects within the application. A complex flow offers a tremendously high security level, but requires the admin to be very familiar with the application and its appropriate use.