Use any 2 power cords to begin with to see which tension you like best. It should be on the lighter side as a beginner.
Begin by placing the balls of your feet on the foot bar. Bring your knees and thighs together and place your arms along your body on the carriage. With an inhale take the carriage all the way out extending through the legs. Do not hyper extend or lock the knees, keep your legs glued together. Exhale and drop the right heel and simultaneously lift the left heel. Repeat on the other side. With every exhale push one heel down and lift the other heel up getting full extension so one heel goes as low as it can as the other heel is going as high as it can.
Start slowly, but rhythmically inhaling and exhaling, keeping your pelvis in neutral position so that you engage your abdominals. This is a really great exercise to strengthen the legs but it is also a good exercise to strengthen the abdominals. Speed it up as you desire, it should feel like you are running in place. When finished, bend your knees back up until the carriage has retracted.