It rarely happens that a master leatherworker is able to properly transfer his/her skills to pupils. And that's why there is a lengthy process of working for an artisan to learn by practice and correction, by constant visual inspection and feedback.
However, if teaching material is organized and conveyed properly, it speeds up the process considerably. This is what Peter has achieved here. All one needs to do is to catalogue a large number of techniques, tips and tricks from his courses.
Here is my result, going from not knowing what's going on to somewhat enjoying my work. I am nowhere near perfect, but I have surely departed the YouTubers level.