Document List Module
The standard options available in all Content List modules:
Set how the content is sorted e.g. alphabetic, by publish date, page, position.
How many articles should be shown at once. A stepper will then be used to navigate to the rest of the articles.
How many columns to display the content in within the module. This can also be set for each kind of device that users may use when using your site.
Content types are the actual pieces of content that get added to a module. For example: A News Article Listing module will contain News Articles. Each one of these articles is a piece of content. When you add a module to the page it will contain an add button. This is where you can add your news articles.
If you have selected to show "Relate items specified below" then you can add content from within the edit module page using the "Find Existing" and "Add New" buttons above.