Data Shield Policies

Hi - has anyone got a suggested data shield policy page set up? I am trying to lock down the site - but still allow customers to create an account and I am not able to achieve this - the data shield is stopping new acounts being created

Protect user accounts YES
Restrict user account creation and management with the following policies

User registrations are limited to these roles do I leave this blank as I want people to be able to create a new account?

Users with these roles are permitted to create new accounts again what should I insert here? currently admin only

Users with these roles are permitted to change sensitive user data: admin only

I cannot find anything about setting up this page at all - so if anyone can help I would appreciate it

Thank you
Sarah