The theme supports multiple locations for sidebar areas. Navigate to Appearance > Widgets to see available sidebars and widgets. For example, for overall site sidebars, in the first step, you need to add some widgets inside your primary sidebar area. The primary sidebar area widgets will show on the blog sidebar, like in the below shot:

You will find the widget-related settings in the Theme Settings > Widget Settings. You can change the Primary Sidebar position from Theme Settings > Blog Settings.