This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
You should think first about the layout of the accordion. If you use tt_content elements, only the header and the bodytext will be displayed. If you use pages and tt_content elements, then the page title will be displayed first. After clicking at the page title, you will see the content elements of that page. If you use tt_news, the categories are displayed first. After clicking at a category, all news-titles are shown. Than you can click at a news-title.
Put your content elements to a folder and select that folder in the plugin.
You can change the layout of the result. See chapter “Administration”.