Thanks for reaching out. Unfortunately, the answer to this is fairly technical. This is something we definitely hope to offer more documentation on, in the near future.
The short answer, is that any plugin which uses a “Custom Post Type”, and generates a page, needs these custom template files. Examples of similar plugins are buddypress and woocommerce. These are 2 top 10 downloaded plugins with the same setup. Check out an example/documentation from buddypress. Concentrate on the header/footer section
The truth is, the contents of these files differ depending on your particular theme. However, they will be very similar to your current, header, footer, and sidebar. In fact, you should start by copying these files. At the worse case, you will be right back where you started, a broken theme, but working on a BePro Listings template.
BePro Listings, cannot possibly know how your custom theme is setup. Themes use html tags to organize data. So if the needed tags aren’t in the header, footer, or sidebar, they don’t exist to BePro Listings. Often times, important html tags are in the theme’s template files like, page.php, sidebar.php and index.php. Remember how these files work, they call header, sidebar and footer. BePro Listings does the same
WHAT TO DO
You would need to alter at least two of the files. The goal would be to place the necessary opening html tags in the header. Then depending on how your theme is setup, you will then need to put the closing tags in the sidebar and/or footer. In the end, bepro listings, will have all the necessary html tags to be formatted correctly in your theme.
All wordpress template files like, page.php, sidebar.php and index.php use the functions for, header, sidebar and footer. So you can see how BePro Listings would completely miss any important structural html tags that are located in template files, since it never uses them
Hope this helps
BePro Software Team