How do I place a custom background on one specific page?

Hello, I am using Clean Journal Pro, my url is https://jenyheckman.com I want to put custom backgrounds on pages. Example under the Spotlight Tab, I'm hosting an author Sadira Stone, I have a picture of roses I want behind the body text (a little transparent). How do I go about doing that? Then if I want a different background on another page, can I do that? If I can only have one background, I can make due I just don't understand how to get it there. Thank you Jeny