1. Scroll down in your report to the "Related Tables and Charts Section" and click the green "Create" button.
2. A new small window will pop up for you to create your headline.
3. At the top of this smaller window you will see a bunch of thumbnails. Click the second one in on the left (this is the Headline Thumbnail).
4. Now select a field and the metric of that field to create your Headline.
5. Click "Save" and you Headline will appear under the "Related Tables and Charts Section".