In this theme we paid special attention to Sidebars for your biggest convenience and on multiple previous requests.
We have two types of sidebar: right sidebar and left sidebar, which can be selected for both of archive and single posts/pages.
In addition to that, you can add/create a new sidebar with VC Widgets/Elements, in this case you will need to go here:
Edit or create a new sidebar, and add any sections you need by means of Visual Composer
For single pages/posts you can add sidebar via Widgetised Sidebar or STM Sidebar VC element