The two most simple ways are to use html. Put this in your header, or the top of your page.
If you want your background to be a certain color use the following code:
If you want to put a background on your page that isn't hexcode but is a color, use the following code:
If you made a picture, and want to put that on your page as your background, use the following code:
For the above codes, replace "#FFFFFF" with a hexcode. Replace "hotpink" with a basic color like blue or lightblue. Replace "image.jpg" with your image url.
