I don't think this video is very helpful. It's rather specific about what's used on big productions but fails to mention normal cranes. If you really want to learn go to a rental house and say you're a beginning DP and ask if you can have a look around.
Sorry to say but this is a bit confusing tutorial if you ask me. The rule is much easier to understand if you are taking about a dialogue between 2 people, which is what mostly happens in movies. In that case, as long as you stay on one side you can put the camera anywhere and you'll be pretty much okay. But with 3 people things get much more difficult. Like in the tutorial: person 1 and 2 talk to each other and then person 2 and 3 talk to each other. But what if person 1 and 3 talk to each other? In that case you already have to put a camera across both of the lines to get coverage.
Also, eye line has not much to do with camera placement. Eye line is mostly important when you do a close-up of an actor and for instance the other actor in the dialogue takes a break. In that case you want to make sure the actor has something to focus on at the same place the other actor was, like a stand-in or even a mark on a wall so the eyes don't go wondering off.
I just cancelled my Netflix subscription. It's not just that there's less and less interesting new shows it's also these silly algorithms that push whatever garbage in your face. It feels more and more like a clickbait website.