There are different levels of permissions in Sitefinity you can apply to your portal. These permissions are to restrict the access of users across your site.
As and example 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.
Please follow this link for Sitefinty tutorials on permissions :
Here are the different types of permissions
- Site Wide Permission
- Page Permission
- Widget Permissions