Once enabled, the plugin will only affect outputs in the context of an article, a category or a featured articles layout and for the categories specified.
|Categories||Select the Joomla! standard categories the articles need to be from (multiple select) to be affected by the plugin.
Note Choosing none will disable the plugin on all categories but it will still affect articles using the plugin’s syntax.
|Subcategories||Automatically selects the next level or all levels of a category|
The selection is done thru the module instance parameters (menu assignments, user access...).