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Does anyone have tips on volleyball approach and arms swinging? - can anyone explain the different volleyball 2009

Can someone please explain the steps and arm movements? I thought I had my footwork down, but I looked online and arm movements were significantly different depending on the steps I did. It feels strange to have the arms behind U in the last piece on the left side of the plant. Can someone explain how this move helps, and approached like to thank you! (im a right-handed)