Each section will pave a _props.pcf file. On a section other than the homepage, you can edit the Section Title and Section Breadcrumb. The _props.pcf file for a homepage is where you can update the contact information in the footer for your site and add additional breadcrumbs preceding the ones for this site. Settings you choose in a _props.pcf file will carry through to all files and folders within that folder.
Content can be added below the left sidebar in several ways. If you only want it to be visible on a single page, use the Left Sidebar Content Editable Region on that page. To display content on multiple pages, the content will be added to a _props.pcf file. Remember, any settings made in a _props.pcf file will carry through to all files and folders within that folder. Add it to the file in the root folder to carry through to the whole site.