To add a sidebar to a static page, navigate to Content --> Edit Web Pages --> Click "Edit" for existing page OR click New Web Page button to create a new web page:





Sidebar options will be under the Display Settings section:





Show Sidebar? setting will display all the available sidebar options in a dynamic way:





After specifying which sidebar to be used, you can select a Sidebar Position for this sidebar:





This is how our page looks like before adding the sidebar:





This is how our page looks like after adding the sidebar: