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As you make your Joomla! site using the extension you will control the details of the display using parameters. Parameters control everything from whether the author's name is displayed to who can view what to the number of items shown on a list.
Default parameters for each components are changed using the Options button on the component toolbar.
Parameters can also be set on an individual item, such as an article or contact and in menu links.
If you are happy with how your site looks, it is fine to leave all of the parameters set to the defaults that were created when your site was installed. As you become more experienced with Joomla! you will use parameters more.