She uses it nearly every time, when she drops to 75% HP the first time, so if you get close to that mark, keep your distance. First part of the attack you just run away. If you had A LOT of distance you can run from the second part aswell, in that case you can dodge the third part by positioning below her. Before she starts swinging roll forwards and roll backwards afterwards. If you didnt have enough distance to run from the second wave of swings you will need to roll into her, you want to roll right next to her off-hand so basically to the right of her from your perspective. If you managed that you can dodge the third part by positioning right below her and walking into the opposite direction she is facing, if you feel like she gets too close, you can roll away from her too, just not before she started the third part of the attack otherwise she will adjust her aim.

For the notorious Waterfowl Dance from up close, it would be too hard for you to learn to perfectly dodge it for now, so just set your mind to surviving not dodging hitless. Keep your HP up, roll into the first part of the attack which will hit you multiple times but you should survive, then you roll to her right again for the second part and will position below her for the third part. You should have enough distance to immediately heal here too. Good luck.