The page you listed above is not any special kind of page. It uses the H (headline) tag in order to divide the page into sections. When a certain number of sections is reached (4, I think), then the Table of contents allows you to jump to different sections on the page.
If instead of linking to a section, you wanted the table of contents to link to another page (as: http://www.vaultwiki.org/books/VaultWiki-Manual)
To do this, you should set up your "Book" namespace. Then, unless you know exactly what your structure is, you should create any new pages in the Book forum. Using the Book tab, you can start adding new pages you create (including other Books) to any Book in this forum.
Since you are required to have a Default area, you can just create a "Welcome to our Manual Repository"-type page that then links (you would add the links manually using the Book icon in the editor) to the manuals in your Book area.
A side note: I see you are having problems with the beta language feature that was just added (see your link). This can be fixed by either adding a Display Title for those namespaces, or making a template edit to vault_search_namespacebit. Find:
HTML Code:
<if condition="$namespace['displaytitle']">$namespace[displaytitle]<else />$namespace[title]</if>
Replace with:
HTML Code:
$namespace[title]
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