It's not easy to follow when things are magically popping up on screen with no indication as to how that happens. Also difficult to follow which objects are being interacted with and in which mode.
Hi Richard,
New bones are added and parented in Edit mode, and constraints and animation happen in Pose Mode.
In the next couple of videos you will see how to create the more flexible version, which goes through the same things I'm doing here.
Stick with it, you can do it.
If you run into any specific issues feel free to create a thread in the forum and @mention me (@waylow) and I'll do what I can to help you out.