I just installed Unami to a domain, and imported everything so that it would look similar to the demo site. It did for a few minutes, but for some reason, just a few minutes ago it reverted back to the pre-import look. I tried importing the txt file again, but that doesn’t seem to be working.
I took a look and didn’t see any of the demo images in the media library. I added those in for you so hopefully that will help you get started. I also assigned the navigation menus to their locations too.
I do see where you changed them out in the theme options. The backgrounds there are the “fallback” ones. To changes the ones on the home page, edit the home page. You’ll see the box where the background images are added there. Give that a shot and see how it goes.