Text over image

I know it’s a long shot because it’s been a couple years but I’m having the same problem; I don’t understand this part:

  • “to get the image “behind” the text you should add the image snippet to an inline background-image style. Since a background-image doesn’t need an alt-tag or sizes your code should look like this:”

Where do you put that code? I think I’ve made the module with text and image snippets but I don’t understand what to do next. Do I make another background image module and add the code snippet for the module to the sytle field in the module editor?