To be able to add RSS Sources to a Collection, you must first have a Collection created.
RSS sources can be added to both newly created and existing collections. Adding RSS sources to a collection does not limit your ability to add articles to the collection from a topic or manually add individual articles.
You can add the RSS feed as a source by navigating to the "manage" button next to Sources in the Collection of your choice.
Now you would paste in the URL of the RSS feed you wish to add and click ‘Add’.
The RSS feed will appear below the text box with the status of ‘Queued for Processing’.
You can compound what you found in Topics with your favorite RSS sources using this method in Collections.
Sometimes you may have errors produced when integrating RSS feeds into your Collection. Find out what those errors mean here.