Sorry to post again, I did a search for what I am looking to do but can't find any posts on it

For my new welcome page I made, I want to add a background image to it using CSS so it does not have the default dark background

The website is www.ultimateforcesocial.com

Can someone help point me in the right direction on how to do it

I tried the following but has not worked

body {background: url('images/landingpagebg.jpg');}