If all your episodes have numbers and you would like them to be ordered based on them use this tag for each one. Episode numbers are optional for <itunes:type> episodic shows, but are mandatory for serial shows.
1. Go to your Podbean dashboard, click "Episodes" ->"Episodes List"->Select episode want to edit->"More Episode Settings".
2. Set the episode number of the post to be displayed on Apple Podcasts (iTunes) to set the order.