The Live Preview is a way to see how the Promoting Contents you add into a Promoting Item will appear in your posts/pages.
Each grey horizontal bar represents text that could appear between your Promoting Contents.
This is only a presentation and not the actual form your post/page will have. This gives you a gist of how your content will be positioned so you can make changes faster and easier instead of having to go back and forth within your post/page to manually check where you have positioned each Promoting Content.
