The markup should go in the ‘Excerpt’ area, not the main content area.
The Excerpt text area is just below the main content area. If you cannot see anywhere to write an excerpt, click on ‘Screen Options’ in the top right of the page/post editor and make sure the box next to []Excerpt is checked.
Note: don’t paste html markup into the main content area when it is in Visual mode, use Text mode instead as the Visual mode can change markup such as < " into code that won’t render properly when you view the page or post.