This lecture was a bit jarring because there was no context. It might be helpful to explain in the beginning WHY we need to redownload models etc because at the point in the course when this lecture currently takes place, everything is working fine.
Also I used a different model from Mixamo and when I went to redownload that model, it still only has Hips and does not have the naming that you stated in lecture.
If its busted beyond this I will dig around and see how to fix it and if I can’t - will resign myself to using the paladin model that is being used in lecture. It sounds like something that the people at Mixamo need to know about. It also sounds like a good opportunity to understand animation since this is a fairly common thing to have to work in (animations in general).
Attached are screenshots of the Ganfaul model I am using from Mixamo and what it looks like even after re-downloading it:
