I've never seen a video that actually lays it out.
The course to be a level 1 instructor (the lowest level) is three days intensive.
Level 2 is four days.
Level 3 is a five day course, plus separate two day exams (on and off snow).
Level 4 (highest level).. well, I'm not there yet, it takes most people three years to do all the training and pass all the tests.
For virtually everyone you have to snowboard/ski full time (100+ day seasons) working on your technique and teaching at least every day for about ten years to pass level four.
The teaching isn't something you can learn from a couple of hour video.