You can password protect a single page, groups of pages or your whole site. Here's how:
Click the 'Edit Site' tab.
Click on the 'Properties' link beside the page you want to password protect.
Enter your password in the 'Page Password' field and click 'Save.'
Password Protecting Multiple Pages With the Same Password
Click the 'Properties' link beside one of the pages. In this pop-up window, click the blue 'Manage All Passwords' link.
You will now be able to enter passwords for each page by entering the password in the text fields next to each page. Click 'Save' when you're done.
NOTE: If you use the same password on several pages, the visitor will only need to input the password once for all the pages with that same password to show. To password protect your whole site, input the same password for all pages.