Single posts template

I created a template for single posts, but when I add or edit a post, neither the template nor its parts show on the editing page. Instead, it shows a blank page when editing.

When I publish and view the page, it shows the content I added into the template–meaning that every post is exactly the same, instead of having its own unique content.

Before I applied a template, it just routed to an error indicating that the single post template was empty. But now that I’ve made one, the content still doesn’t show.

The page I need help with: [log in to see the link]