The left hand navigation is not part of the login design area.
Overview
The Password protected area is a custom area within a site that allows a user to view a page (and children) via a custom login area. The authentication is done via a predefined password that is generic to the login area. A username is not required.
When requesting a password protected page/area within a site there are 2 options.
1. Use the WDS generic password (Simple)
2. Create a generic user account specific to a site with custom user/password (Complex)
Example of the login page can be viewed at https://www.designsystem.sa.gov.au/features/landing-page-features/password-protected-area(you may need to log out to see the login screen)
Add this feature to your site
The Password protected area is a custom implementation that requires manual installation by the WDS team.
Instructions to add a Password protected page/area (requires log-in)