WP RSS Aggregator is a WordPress plugin that creates a feed reader/aggregator on your WordPress site. It works in a similar fashion to RSS readers like, for example, Google Reader or Feedly. See our feeds here.
In the documentation of the plugin they list a series of steps to get started.
Set the General Plugin Settings of your choice, followed by the General Display Settings. Click Add New to add a new feed source. You will need to get the URL of the feed and enter it into the box provided. Include the “http://” in the URL. This may be in this format: http://www.wpmayor.com/feed. Instead of ending with “feed” it may end with “rss”. Choose a limit if you want. Set other options. Publish the feed Source.
Display the feed items. Feed item display is controlled via the shortcode [wp-rss-aggregator]. This shortcode accepts a number of different parameters.
Shortcodes are not only limited to usage within posts and pages (the content editor) but also directly in the code of your templates, via the WordPress function do_shortcode().
So the general format for running a shortcode outside of the post editor is as follows:
// Use shortcode in a PHP file (outside the post editor). echo do_shortcode( '[my-shiny-new-shortcode]' );