To customize your experience’s background, go to the Design section and click the “Painter’s Palette” icon, then click Background.
A secondary slider panel will open where you can edit your campaign’s background. At the top of the slider, you can choose a background color from the preset theme in the Theme Colors area.
The next option down is Other Colors where you have even more choice, or you can use the “Dropper” or “+” icon to select a custom color or add a specific hex code.
Once a background color has been selected, you can also choose a Color Pattern.
The last option in the slider menu is Upload Image. Simply click on the empty image box to select a file from your computer.