Inside the list of episodes in the feed, you can find switches to adjust the availability of each episode for listeners. Publishing episodes will make the content available to listeners. Unpublishing will remove the content from all listeners' feeds.
If you're scheduling the episode in a Date-Based feed for a future date, flipping the switch will change the status to Scheduled. It will be made available for listeners when that day and time comes. If left Unpublished, the content will never be made available to listeners.