background body

I am working with a template and gave some elements a background color. But the rest of the page i want to have a background picture. Template can change later so the name is not important.

How to put in the correct code for having a background picture and where do i put the code

First of all, we need precise information:
 
Template name and version 
Astroid version 
URL? 

Have you seen and tried the UIKIT module Backround-Slideshow?
www.joomlaplates.com/login.html?folder=Uikit%2B3%2BModule

It would be nice if you could answer my questions in an already opened thread before opening threads on other topics. 

Or can this be closed here? 

Thank you.