The knots for tatting are like macrame knots. They're very simple. I think it's harder to understand when you're looking at someone using a shuttle for several reasons. The thread is tiny, their hand often blocks some of what they're doing and the shuttle moves in a way that is most efficient, rather than easiest to understand.
What I mean by that last part is that the shuttle doesn't move like a needle and thread, where you just need to follow where the tip of the needle is going. The lead tip of the shuttle can be either end of the shuttle, as it moves back and forth. You could use just one end of the shuttle as the lead tip, turning it as you go, but that would be inefficient. It would be much easier to learn and understand, but it would be inefficient and take much longer to do.
When I teach people to knit, crochet, macrame, embroider or do beadwork, I usually show them using larger materials. I think it helps people see and learn the movements. After they get the basics, then we move to smaller materials. I know how to tat, I've just never taught anyone, for some reason. If I did, I would use some large cord and not even use a shuttle to start with, just a length of cord. Or maybe a small piece of cardboard with notched ends as a shuttle.
Maybe try looking at some diagrams of some of the knots and try duplicating it with larger cord. After you get the hang of making a couple of the knots, then go back to watching the videos. They might make more sense to you, then. I learned from looking at diagrams in a little booklet. When I first started practicing making crocheted lace, I did not start with fine thread!
