Location: All Folders mode - right click on Item - select Properties - select Authentication tab.
This page requires authentication: Check this box if a username and password are required to access this topic. Entering a username and password here can, where the web server hosting the page uses HTTP authentication, automatically present the user credentials to the server when the page is requested. It does not fill in a form in a forms-based authentication mechanism.
User Name: Enter your username for accessing this item in the text field.
Password: Enter your password for accessing this item in the text field.
Apply settings to child items: Check this box if the same username and password should be supplied for items nested A display mechanism that shows a related item below and slightly to the right of the item above it beneath the selected item in the tree.