How to change a solid background color:
Click anywhere on the design background.
Select the color swatch in the editor toolbar above the design.
Select one of the template colors, Brand Colors, or select a new color using the color picker or by entering the Hex Code. There are also Gradient options here as well.
To change the background to a photo or your own uploaded graphic:
Select the GRAPHICS option in the upper left.
Select the PHOTO AREA option.
Select the FULL PAGE option.
Select the ALL GRAPHICS option.
Select FREE PHOTOS or UPLOADS and find a photo you want as the background.
Then click on one of the photos and drag it over to the design, it will apply it as the entire background.
To delete a background:
Select the background on the design.
Select the trash can icon in the upper right in the editor toolbar.