Base URL: This is the URL of your site’s homepage, e.g., https://acme.com.
Location of search results page: In the context of the Portal App, the search results page is a regular page that is equipped with a few special widgets providing the functionality needed to display clickable search results, “search again” and “load more” buttons, etc. You can copy this page from one of the original portal sites (via another working copy), paste it to your new site, and specify it here in the site settings.
Header, sidebars, and footer: These layout elements are disabled by default. Switching them on as needed allows you to globally add standard elements such as a top-level navigation, breadcrumbs, etc., to your pages via widgets. To edit these layout sections, switch to “Edit layout” in the top bar.