You need to assign the appropriate members---user accounts and other security roles---to each of your security roles. You need to be a member of the Symantec Administrators role or a member of a role that has the Change Security privilege to add members. You can assign a user account to any number of security roles. The members of a role have all of the privileges and permissions that are granted to the role.
You can add a role to multiple security roles, but you cannot create a circular membership where a particular role becomes a member of itself. A member of multiple security roles has the union of all the privileges and permissions that those roles grant.
To add members to a security role