Personally, I found it quite difficult to follow these video tutorials, despite my very positive opinion of the source as a person. I don't want to mislead anyone and say that his video tutorials are very good. However, the person did put in the effort to create them, and with their help, you can, albeit with some effort, figure out what and how.
For now, I'm more interested in working on mods than writing tutorials (I suspect Footman feels the same way). Perhaps, in the future, the situation will change, and I will try to write a detailed manual with pictures, but for now, I'd rather spend time on mods.
Anyone who really wants to understand this process can put in a little effort right now and figure it out using the source's tutorials and some other old information.