This is an introduction to sidebar positions made available for your website when using this theme. Positions are available more for the pages than blog posts, but your blog still gets some of the 20 locations. Sidebar groups that sit side-by-side will have dynamic widths which means you can have up to four(4), but when you publish 1, 2, or 3, they will self-adjust in width to fill the space the fourth one would normally take up.
The left and right sidebar positions are separated for pages and the blog archives. This was done so that you can manage your widgets much better when it relates to the blog or to static pages that are not connected to the blog.