Footers layout

Hi, I am using the Business Key theme and I would like to add more than one footer to the site I am developing. I mean the footers accessed via Appearance/Customize/Widgets.
When I try this the two footers appear side by side. How can I make them appear one above the other or ‘stacked’? Is this possible?
I’m sure this is fairly obvious, but I am new-ish to WP and have a mental block about this, just can’t see it at the moment.
The point of having two stacked footers is so that I can have a banner with logos in it on a white background, and then other text stuff in the second footer on a blue background.

Thanks in advance, John