Contact the water in a proper pitch attitude, and slow to idle taxi speed.

Bottom line

As the seaplane approaches the water’s surface, smoothly raise the nose to the appropriate pitch attitude for touchdown. As the floats contact the water, use gentle back pressure on the elevator control to compensate for any tendency of the nose to drop. When the seaplane is definitely on the water, close the throttle and maintain the touchdown attitude until the seaplane begins to come off the step.