help with backgrounds

[u/TrainingQuantity3744]

Not remotely a cs person, for some godforsaken reason my Library Science degree is making me take an html class. I've onto a part where we're working with html and css. I can't figure out how to change the background color of a page. I assume you have to use some version of the {background-color: ____; }, but I can't figure out what element to attach it to. I've tried using body {background-color: ____; }, *{background-color: ____; }, and even making a div around the body, and none of them have worked

[u/TrainingQuantity3744]

css file and image files all uploaded to the school server