Sometimes you need to be able to control who has access to specific pages in your site. In Google sites, you control this access by enabling the page-level permissions. By default, the permissions are turned off.  To enable permissions, select Sharing and Permissions from the More actions menu. At the top right of the Sharing and Permissions page, you should see a link Enable page-level permissions. Click this link. Then select Turn On Page-level Permissions.

Google provides an excellent Getting Started Guide which you should read prior to setting permissions in your site. This guide explains why you might want to use page-level permissions, gives detailed instructions in setting them up, shares how pages inherit them, provides an example of the permissions in action, and shows how to turn the permissions back off. If you have given groups access to your site or have a public site, it is important that you read the Common Issues section.