Have you seen the tutorial here:
https://www.zen-cart.com/tutorials/index.php?article=80

From your first post, is this the banner group you've created and
trying to use:
Banner Title: * Required
Banner URL:
Banner Group: bottombannerWide-Banners, or enter a new banner group below

If so, you need to go to Admin/Configuration/Layout settings,
and edit footer or header banner settings to reflect your new banner group.
Example:
Banner Display Groups - Footer Position 2 Wide-Banners
to
Banner Display Groups - Footer Position 2 bottombannerWide-Banners