Hey Iionflight,
first of all, thank you for the purchase!
To display custom backgrounds on individual pages, please use the “Background Slider/Source of Images” settings box in the page editor mode: you can choose to source the images from the attachments of the page in question, from a custom folder on the server, or from NextGen and other third-party plugins. I would recommend using the “custom directory” option, so that each individual page has its own folder with a background. Please let me know if this helps!
Sincerely,
Andrii / Satori Studio