Widgets can be added to the side-bar area of a page.

Some Themes have Widgets enabled by default, in this example they are on the left hand side of the home page.

To remove go to the ‘Widgets’ area, then click the downward arrow next to each ‘block’ and delete them.

The side bar area will now be empty:

For info on using Widgets, see this link: https://docs.campuspress.com/en/categories/25-widgets-sidebars