Setting up Portal Users Permissions in Portal Site
You can set up permissions in order to restrict the access of users across your site. Your site can have public facing pages with no permissions. However, if you need to display pages, widgets or navigation links based on the logged in user role, you can set up permissions at Page Group, Page or Widget level.
Apply Security to Page Group or Page:
In the context menu go to Pages, click on "Actions" for your respective page group or page. From the dropdown, select "Permissions".
Under the section "View this page and its child pages", you can click "Change" to select the role to assign view permissions.