@Sarah, I think your confusion shows that the message around the theme is not clear and could be confusing for some users. It says it is made to work with Elementor, but should say it is made to work with Elementor Pro.

I tried the Hello theme out on a test site. You are correct that there is no access to the footer. There is a PHP template file for the footer but it is empty and there are no footer options in the Customizer.

In terms of the header, the Customizer has the WordPress site identity menu item where you can change the site name and add a logo. Also, I was able to add a menu. The PHP template file for the header includes these, but they show totally unstyled stacked down the page, not horizontally as one might expect.

I guess there are no widget areas defined in the theme, so the customary widget management interfaces in the Customizer and under Admin / Appearance don't exist.

I installed Elementor Free as prompted. That did not change anything. I'm not sure why anyone would use this theme unless they were using Elementor Pro. If you are using Elementor Pro and want to totally style the theme, header and footer using Elementor Pro then it might be a good choice.

It is a free theme, so you cannot complain :) If the marketing clarified that it is intended as a blank slate for use with Elementor Pro then I don't see any issues.