The Joomla! Categories Assignment provides the functionality of assigning your box to articles which belong to one or more categories which you have selected specifically.
In the table below you can see which options are available to setup the Joomla! Categories Assignment.
With this option you are presented with the entire tree of all your available categories.
You are able to select from one to all of them just by checking the checkbox to their left.
|Also on child items||This option gives you the chance to choose if you want the box to also be assigned to the child categories of the category selections that you did. The expected behaviour would be "Yes" but naturally you are able to either exclude them or even include only them.|
The Page Types are two. The Articles and the Categories. This means that you can choose the box display on article pages and category pages which are basically lists of articles.
Click in the textfield so a selectbox pops up from which you can filter the Page Types that you'd like by typing on the fly.
Once you select one you can continue typing to find the next one and so forth.
A very common use case for the Joomla! Categories Assignment is when you have created a very thematic category which can fit perfectly with an equally thematic box.