Setting up Users and Groups
If you're managing a network that uses Active Directory or LDAP, you can configure FreeNAS to consult either instead of having to input all the user details.
However, if you aren't using one of those databases, you'll need to use the internal one. Thus if you're using a sharing protocol or other service that's configured to use local user authentication, click Access > Users and Groups on the main FreeNAS menu. Then manage the groups and add the desired accounts.