Customize - Background Image
What a statement a custom background image can make! The theme allow you to customize the background of your blog by either uploading an image. To get started, open the Customizer. Not familiar with the Customizer? Just hover over your blog’s name in the top bar and click Customize. Once it loads, look for the Background Image section:
To upload a background image, click the Select Image button and you’ll be able to select an image from your media library, or upload a new one.