The first page of any site is called Welcome Visitors. It is the page you see if you specify no other page in a site's URL. One click takes you to this page for any site.
The flag is the colorful square by the title of every page. All pages from a given site carry the same flag.
Click the flag to start browsing at the site's Welcome Visitor's page.
When you Follow Links to pages on many sites you will see many different flags.
When you click a flag you start your browsing over from that site. That site becomes the Origin Server for your continued browsing.
When sending links to a page by email consider following links from the beginning to the page of interest and sending the whole sequence to provide context.