registration validation

Hello,
I am completely new to using CB.
I have a very basic question, please forgive me, but I couldn't find the answer in the documentation.
I want when someone registers, the moderator will receive an email with a validation link. How to define who is a moderator? And specify the email address of this one? And how to activate this approval process?
Thank you for your understanding and help,
Mark

Registration approval can be enabled within CB > Configuration > Registration by setting "Admin Approval" to "Yes".

As for who is a moderator that's entirely based off the "Moderators View Access Level" parameter in CB > Configuration > Moderation. That is a Joomla view access level so anyone with the usergroups matching that view access level would be considered a moderator. The email address of their account will be used.

Your moderators will then receive an email that a registration is pending approval. They can approve registrations from the "Moderate User Approvals" Joomla menu item type or using the CB Workflows module which will show you how many are pending approval with a link to the page.

Hello,
Thank you very much for your answer which helps me a lot.
Unfortunately moderator users do not receive the information email that there is a pending approval. However, this may be linked to the fact that I get the message "Column 'name' cannot be null" when registering a new registration although in the registration form there is first and last name.
Thanks for your help.
Best regards
Marc

Here is the screen capture :

Thank you.

It's not possibly for CB to attempt to store a NULL name as we've multiple fallbacks in place. My guess is you've a 3rd party plugin causing that, which would likely be acting on Joomla user store events. You've 2 warnings from a 3rd party Joomla user plugin "ajaxregister", which could be the cause.