Since I've been using short cuts all the time I haven't realized what's happening under the hood.

Now I can say that I know something about weight painting when it comes to rigging.

Thank you very much Wayne!

After weightpainting, the head bone moves the entire head instead everything except the ears. This was the second attempt to get it working. In the first attemt, the head bone worked as expected, but the ear-bones only moved the part where the ear transits into the head.
I painted the vertex weights just as in the video shown (using 2.91.2).

I think these are one of the things that I need to understand well, and that has given me a little headache for not knowing exactly how it works.

Is it mandatory to keep underscore between Suzanne and rig? Can't we keep space between them like Suzanne rig and not keep it like Suzanne_rig?

Hello, this video doesn't work!

Thanks for the great introduction. Unfortunately, symmetrize didnt work when I tried to mirror the bone with it.  Symmetrize simply did nothing. So the whole construct kinda collapses and only partially works.