Sidebar not showing and Elementor

Hi there. I have two problems I’m looking for help with:

1. I can’t get the sidebar to show. Under Customize -> Appearance -> Global Sidebar Layout, no matter which option I choose, the layout does not change. Additionally, under Customize -> Widgets -> Primary Sidebar, whenever I try to add a widget to a sidebar, it says “An error has occurred. Please reload the page and try again.” No matter how many times I reload the page, nothing changes.

2. I usually edit my pages with Elementor but when I go to do that I get an error saying that the content area was not found on my page. Elementor support says that this happens because the theme’s template does not include the_content, and this cane be fixed by pasting <?php the_content(); ?> into the template. Where in the template do I paste this? Alternatively, is there any other way to get Elementor working with Surplus Concert?