Thanks! Now that I know what to call it officially, I did a search and found this!
I had to rt click on the video link and save it to get it to open. But I think I understand it now! Just need to know if I cut off the working yarn that I was using on my circulars and then cast on my dp's to start the I cord. Or do I leave that working yarn on my circular, and start new on my dp's for the I cord?