The Enterprise Sample page is available at http://your-server:port/portal-ID/welcome/.
This is the welcome page for Portal Server samples.
Follow the link on the welcome page.
The URL will look something like this: http://your-server:port/portal-ID/dt?desktop.suid=uid=authlessenterprisesample,ou=People,o=EnterpriseSample,dc=your-dc.
Login as Mary with password mary, Chris with password chris, or Ed with password ed and observe the difference in the portal content based on their roles.