When converting from DWG to a Revit model, the Revit family type cannot be selected. I downloaded the Helix trial few days ago, but the Revit family type cannot be selected, and I am also unable to create it. I will provide a video for you to review.
Can you try running it with the attached model and Helix mapping settings? If so, it might be something related to the Revit file / template you are using. If so, are you able to share the Revit file with me, so I can test that too?