you get three Sidebar options; viz. the right sidebar, left sidebar and an option that disables the sidebar.

You can find settings under Appearance > Customize > Layout > Sidebar

You can set a sidebar for entire site with Default Layout option.You can set a sidebar for particular Pages, Blog Posts, Blog Post Archives as well.

When one of the sidebars (left/right) is set, you can adjust its width.

Note: When you activate the addons for integrated plugins like WooCommerce, LifetLMS etc. you can see related option to manage sidebars

also allows you to manage sidebars for a particular page or post through the meta settings.