Hi Tim
Thanks for contacting us. Don’t worry we are here to help you.
1) For removing solid Grey background-color, kindly add the CSS code below in Additional CSS Box. Please go to the Appearance => Customize => Additional CSS then paste the CSS here and click to Publish button.
body.page-template-default #wrapper,
body.page-template-default .theme-bg-grey {
background-color: transparent !important;
}
2) To set the background image of the pages, please go to the Appearance => Customize => Background Image now select your background image and click to Publish button.
Let us know if it solved the problem.
Thanks