What's a Podcast?
A podcast is essentially a radio show that you can get on the internet, so you can listen any time you want. You have two options: you can listen to a podcast through a website (this is called streaming). Or, you can download a podcast, which means you're saving it on your phone, or tablet, or computer, and you can listen to it anytime, even without an internet connection.
To Stream: Chose a podcast episode, and click the play button.
To Download: Get it delivered to your phone or tablet each week using an app.
For iPhones and iPads, use the Podcasts app. You get it from the App Store (it actually comes installed on newer devices). In the Podcasts app you search for Serial and then hit subscribe.
For Android phones and tablets, try the Stitcher app. Get that from Google Play. In Stitcher, search for Serial and click the plus sign (+), to add it to your Favorites List. Now go to the Favorites List. Tell it to download new episodes by clicking the gear in the upper right corner.