What are the options Singulars and Archives?
Content on a WordPress site is often displayed in two ways: singular state and in archives. It is possible to target a condition group for each of these alone or combined.
The Archives option is self-explanatory; this makes it possible to display a sidebar on the blog page, post type archives, taxonomy archives, author archives and so on.
The Singulars option makes it possible to display a sidebar together with content in its single, unique state. This can be a single post, page or custom post type. It can also be content in a category or with a tag, or content written by a specific author.