Inside the <body> tag of your HTML document
you will have to add some HTML scripts. Take a look at the blank example
I have below and try it out on your own web page. This changes your background
to ...uh...Red. Try different colors. (Spelling counts.)
You can also try colors such as lightgreen,
<html>
<head>
<title>Welcome to my home page</title>
</head>
<body bgcolor=red>
</body>
</html>