I think there's a video made by GermanFS about how to do patw, but I personally think that you must have done Alatw, Almatw those kind of tricks before you can land a proper Patw imo.That's the way you leg get more flexibility and faster so once you made it.You can start to training patw.
This is the cleanest patw I have done imo, the first one

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Worse Training part II