Placement targeting puts your ads on individual sites in the Google Content Network. Site sections take that one step further by placing your ads on only one section or even one page of a site. If you sell soccer shoes, for instance, you might choose to advertise only on the sports section of a news site rather than placing ads across the entire site.
(Note that site sections are different from publisher-defined placements. In a publisher-defined placement, the publisher decides what pages or portions of his site you may target. With a site section, you yourself use URLs to pick which parts of the site you want to advertise on.)
Select a site section by entering its URL on the 'Add Placements' or the 'Edit Placements and Bids' pages, which are linked from the Placements tab of your ad group. If the full site is example.com, the section URL will take the form example.com/section. When targeting a certain section of a site, your URL may only include up to two section levels below the home page: example.com/section/subsection/.
You may also target individual pages by using the form example.com/section/page.html. Even though you're limited to two section levels when targeting a section of a site, there's no limit to the number of section levels that may be included in a URL for an individual page (such as a URL ending in .html).
Please refer to the actual site you wish to target to see how its sections and page URLs are defined.
To learn more about advertising on specific sites , please see What Is Placement Targeting?
