You can import users that are already authorized for ESM. You need to have at least one role available in ESM for Fusion to assign to these users.
In the ArcSight Console, ensure that the External User ID and E-mail fields for each account comply with the following format:
name@domain.com
Log in to ESM for Fusion.
Click ADMIN > Account Groups > Import Users.
Select the role that you want to assign to the imported users.
Select IMPORT USERS.
As you add more users to ESM, you can run the import process again. ESM for Fusion ignores duplicates of user accounts that have been imported previously.