The Outset Theme has two sidebars, left and right. These sidebars can be selected for archives as well as single pages or posts. You can create additional sidebars using Elementor widgets. These additional sidebars can then be added to individual pages or posts. You will have options from single pages and Theme Options.
To set up the sidebars, click on Theme Options > Advance > Sidebar in the WordPress menu.
To set up the sidebars, two sidebars, left and right You can from Appearance -> Widgets.