Complex sentence: A podcast is an episodic series of digital audio files which a user can subscribe to so that new episodes are automatically downloaded via web syndication to the user's own local computer, mobile application, or portable media player.
Split into simpler sentences: A podcast is an episodic series of digital audio files which a user can download and listen to. It is often available for subscription, so that new episodes are automatically downloaded via web syndication to the user's own local computer, mobile application, or portable media player.