1. Click on the "style" icon to bring up the page options.
2. Under the "Background" panel, here is where you can either add or select an image to be placed as a background.
3. To add a new image, click on "Select".
4. Click on an image, upload new, or choose from the web.
5. You will then see your background has been set to an image. You can play around with and toggle the different the background sizes.