Adjust the incline of the back padding to your desired angle, the steeper the harder. Then adjust the leg padding to be your desired end point of the movement. Hold on to the handles and position your back in the centre of the padding.
Start by raising your legs upwards in an arc motion until your knees are approximately parallel with your shoulder or to where's most comfortable before. Then in a controlled manner lower down until your legs touch the padding. Activate your core throughout and keep your upper body stable. Maintain a slight leg bend throughout. Repeat for the desired repetitions.
Avoid using momentum by kicking your legs up or dropping them down.