Hi Lola,
We requested the login URL to check for the option in the Customizer section, In the Pro themes sidebars can be enabled in several ways, the first is to select page layout with sidebar, for this please navigate to Dashboard > Appearance > Customize > General Layouts > Page Layouts and chose your prefered style which includes sidebars, here is the screenshot: https://nimb.ws/Pk14rf
The pages which are not listed in this customizer section can also use sidebars via page options, please navigate to Dashboard > Pages > Edit page > Page Options > Show Sidebar
Please make sure that widgets in the sidebar areas are added from the back end, please navigate to Dashboard > Appearance > Widgets and check sidebar areas are filled with widgets you want to be displayed.
Kind Regards