Have the balls of your feet placed on the platform and heels hanging off it.
Drive your heels upward to lift the weight.
Steadily lower the heels down until your calves are fully stretched and repeat.
Using momentum to drive the weight up and down.
Feet being too wide or narrow, keep it should width.
Upper body swaying with the movement, keep it still.
Seat yourself in the machine with your feet pointing forward and spaced roughly shoulder width apart. Position the balls of your feet on the platform so your heels are hanging off. Adjust the padding firmly against the lower end of your thighs.
Start by driving your heels upward and release the safety. Steadily lower your heels downward until your calves feel fully stretched. Pause briefly then drive your heels back up as high as comfortable. You should feel the weight on the inside of the balls of your feet when performing the exercise. Once you have completed the desired amount of repetitions pause at the top of your final movement, engage the safety and lower the weight down onto it gently.
Avoid using momentum to bounce up the weight.