The playlist widget is available in your widget list with the title Podcast: Playlist. This widget give you the ability to display a playlist of episodes (either your own selection or all of the episodes from a specific series) – the playlist uses WordPress’ built-in playlist functionality and, as such, is easily styled by your theme.
The widget allows you to supply an optional title that will appear above the playlist, as well as which episodes you would like to be included in the playlist. You can either select a series that you would like to display or you can provide a comma-separate list of the episodes you would like included in the playlist, which would look like this:
5,19,8,46. The episodes will be displayed in the order that you input them into this field.
If you leave the widget with the default setting (no episode IDs specified and no series selected), then all of your podcast episodes will be displayed in the default order that WordPress provides.
If you would like more control over the display and content of your playlist then you can use the podcast playlist shortcode instead.