You can use through the Authentication policy.
1    Go to Authetication System > Authentication > Policy click Enable user authentication

2    Click on Add, after that configure the authentication policy
3    After doing the above 2 steps, the authenticated user will automatically added to the default group (you can choose to add to other group). Go to Authentication System > Local Users > Users, if the user in Users is identified as a local user, the user who is not in Users will be recognized as a new user when next time access to Internet.

4    After users completes the authentication and after binding relation exist in Users, then modify the New User Option to No authentication for new users.

You can use through the Authentication policy.
1    Go to Authetication System > Authentication > Policy click Enable user authentication

2    Click on Add, after that configure the authentication policy
3    After doing the above 2 steps, the authenticated user will automatically added to the default group (you can choose to add to other group). Go to Authentication System > Local Users > Users, if the user in Users is identified as a local user, the user who is not in Users will be recognized as a new user when next time access to Internet.

4    After users completes the authentication and after binding relation exist in Users, then modify the New User Option to No authentication for new users.