There are several parts to creating a podcast to which your viewers can subscribe. The order in which you do this is not as critical as that every step is done.
To create a podcast - go to the Settings option under Media, select Podcasts and click Add Podcast. Filling out and saving this form will create a podcast feed that can be use when creating a podcast service on iTunes or Google Play. After creating the podcast service on iTunes, Google Play or other service, you can edit the podcast feed on your website and add the service's url in the Service section to give subscription options from the podcast feed page. If you still need to set up your service come back and add it to your podcast later.
To add media items to the podcast, add a new or edit an existing media item
add a new or edit an existing asset in that item
designate which podcast(s) should include the asset. Keep in mind that Asset file formats must be either M4A, MP3, MOV, MP4, M4V, PDF, or EPUB to be added to a podcast.