The Session Type screen prompts you to select the type of operation that you want to perform in this session of using the migration tool. There are three options to choose from:
During the setup phase you must select the databases to migrate and setup devices and work databases to use for the migration process.
During the migration phase you must first identify the database objects within the selected databases than you want to migrate, then watch as those objects are migrated.
The third option - validation - allows you to verify that the databases and object that you selected have been successfully migrated.