What is the sidebar
The sidebar is a column on the right of the page. It contains links, with excerpts, to the latest posts.
It uses the _includes/latest-posts.html file, so if you would like the sidebar to contain different content, then you need to override this file.
Sidebar Visibility
If you want to show the sidebar with latest posts then set show_sidebar: true in the page’s frontmatter, or in the defaults in your site’s _config.yml.