This is currently done through the Mix Down dialog (accessible from the File menu), however we are aware that this isn't terribly obvious and is a rather overly complicated approach, so we are planning on returning to a more standard "Export..." option in future releases.
This is currently done through the Mix Down dialog (accessible from the File menu), however we are aware that this isn't terribly obvious and is a rather overly complicated approach, so we are planning on returning to a more standard "Export..." option in future releases.