How to get background like the demo.

Hello
On your demo at http://www.acmethemes.com/demo/?theme=corporate-plus-pro
as you scroll down the page, there are several places where the background changes. You have one image for the Featured Sections, one for featured sections, one for the Interested Sections, one for the Testimonials sections, and one for the send us email section. I am not understanding how you are doing that and our instructions on the documentation page doesn’t explain this.
We are trying to get a similar look on our site at https://conference.narsol.org/, but as you can see the same background image continues throughout the site and the only image that appears the way we want is the header on the bottom.

Thank you.