In this step you can design form background as much as your choice.There has many kinds of options.Such as
You can set background image, color, link, blend mode, repeat, position, size on this section. You can positioning the background image via Background Image Position property.The Background Image Repeat sets how a background image will be repeated.The Background Img Size specifies the size of the background image.
In this step you can set border color, width, radius.There have different types of border.Such as solid, dotted, dashed,double. You can set hover border also.
By Padding properties you can generate space around of content.
4. Margin :
By Margin properties you can generate space around of background.
You can set background shadow by using this property.