How do I record a second track in an existing session?

[ellis@hillinger.org]

I see how to open an audio file while I'm in a session, thank you. However, what I want to do is play this recording as one track while I record a second track. Opening an audio file only plays it back - it doesn't add it to the "Other Audio" column so I can work with it. Furthermore, your tutorial https://www.youtube.com/watch?v=Gn-dOqnNLoY indicates there should be a "Make a Recording" button at the bottom of the second column.

Thanks!