If you select menu entry Extensions > Modules, you are shown a list of up to 20 entries:

In this example, we can see that some are inactive, as shown by the red icon. The value shown in the Position column determines where on the page they will be displayed. Note in particular those showing as “sidebar-b”, as these will appear in the right hand column.

Many modules have a set of attributes to allow you to fine tune the way they work, and/or the amount of detail they display.

When specifying whether or not to use and display, you can choose whether the particular module is to be shown on every single page, or only on nominated pages. If the latter, for every page accessible from a Menu entry, you can then declare if the module is to be shown there. By this mechanism, the module for “Stop Press” Articles is shown on the home page