If you want to have both an audio version and a video version of your podcast, you'll want to create 2 "Podcast Channels".
In WordPress, go to PowerPress > Podcast Channels.
First, edit the default channel. This channel will be your Video podcast feed. Give it an appropriate name, description, and landing page URL.
Then, create a 2nd channel. This channel will be your Audio podcast feed. You should probably give it the same name as the first channel, but add (audio) at the end. For example:
Restaurant Engine Podcast (audio)