Flip turns annoy non-swimmers trying to learn more than any other aspect of the stroke.
Ok, that’s an overstatement, most triathletes could care less if they can do a flip turn, they see no value in it. While it conserves momentum, it requires you to hold your breath while heart rates are up. Triathletes don’t like holding their breath.
Can’t blame them.
Running or cycling while holding your breath just doesn’t work well.
Swimmers train for it. Primarily because the flip turn used for competition is a faster more efficient way of changing directions. You don’t really need it if you are an open water swimmer or triathlete, but it can make practices smoother if you can get the breath control.
How do you do it?
Well there are a great number of youtube videos dealing with this issue. I might make one myself at some point when I get some good underwater camera equipment.
I recommend learning in phases: spend some time doing summersaults in the water forwards and backwards in the middle of the pool after 4-6 strokes. Get the feel for it. Then do the turns from a flat non-moving position. Then do the turns without moving close to the wall. Then put it all together.
Importantly, the rotation moves the hands from the sides into a streamline position. It also requires you to flip into position to push off. In other words you flip in the most efficient way to the exact position to push off.
I’ll say more when I can get a few pictures lined up for explanation.