While this seems like a simple question, there is a ton that goes into paddling technique. You can find many resources and videos online, and I'd suggest you do some research to really dig into this question.
That being said, the basic technique is pretty straightforward. You stand perfectly parallel to the board facing forward with your feet about shoulders width apart. You should be centered on the board in both directions. The hand slide is a good marker. Your knees should be bent slightly. With the angle of the blade angling away from you to the front, dip the paddle in the water a few feet in front of you. Don't lose your balance, but the further forward you can reach, the more power you can attain. Dip the paddle in the water and try to pull it back straight parallel to the rail of the board, but don't hit the rail. Pull the paddle out of the water immediately as the paddle passes your feet. As you pull the paddle out of the water, drop your top hand across your body so the paddle blade turns and slices thru the air as you move it forward for the next dip. When you're stroking, concentrate on keeping your arms straight and using your core to power the stroke. Think in terms of your top arm and the paddle forming an "A" with the middle part being the crossbar in the "A".
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