Registered users can be created in a couple of different ways; either manually by the site administrator, or by the user themselves.
To manage pages, log in to your site with the ‘siteadmin’ details received in your ‘Welcome Email’.
As the site administrator you can add new users by simply adding their details from within your Content Management System (CMS)
Once you have User Groups in place with Users assigned to them, you can then set page permissions to allow only certain users to see certain pages on your site