You can upload an episode to Buzzsprout and schedule it to go live sometime in the future. When you’re
uploading your episode, select the "Schedule for future" option.
The episode will show on your Episodes page and will display the date it will be published. You can always change the publish date, and even remove shows from your feed by "Unpublishing" them.
Note: Keep in mind, if you upload episodes to be published in your next cycle, the time for that episode will count against the allowance for the cycle in which it is uploaded, not published.