How to set up the private area 

Go to 'standard pages' in the 'manage website' menu click on 'add private area'

There is only one private area option, once it has been added to your website it will appear in the standard pages list. Once in this list it can be disabled or enabled just like any of the pages can in this list.

To make it a truly private area you need to set permissions separately to restrict it to those chosen to read and / or edit all or parts of it. 

NB. Permissions set in the private area do not feed back to your main site, but they are managed in the same way.