You use the early ATM process forms as input to more complex forms later in the process. You use the final ATM process forms when you create the physical objects in your database, ensuring that the universe of domains, constraints, table accesses, and reports and queries are understood well in advance of the process of creating the physical database objects that derive from those constructs.
The ATM process is the first step in the transition from your logical data model to the implementation of your physical data.
The second and final step in that transition is to collect or prototype data demographics.