Hello,

I visited the URLS you provided. If you want to add background to the brands slider you need to Go to Theme Settings >> Footer >> Pre-Footer area.
And Edit the HTML Block used there.

Screenshot for Clarification: https://www.screencast.com/t/hgXb3b3KR

Then you need to edit the HTML Block and add a background-color as you require. From Edit Row >> Design Options.

Screenshot for Clarification: https://www.screencast.com/t/izOqAufcEr1

It will change the background of the brands slider that is coming before the footer.

As for the homepage you want to display it without background-color then you need to edit the home page scroll to the bottom. Disable Pre-Footer area.

Screenshot for Clarification: https://www.screencast.com/t/mjxMVt2j

Then you need to add brands slider using the Wp-Bakery Brands Module at the bottom of the homepage.

Screenshot for Clarification: https://www.screencast.com/t/4xIf8Wn3

Best Regards.