Deadlift the kettlebell to a normal standing position, brace your abdomen and pull your shoulders down and back to support a neutral spine. initiate the swing by driving your hips back and pushing the kettlebell slightly behind you and bending your torso forward from the hips. As soon as the kettlebell hits the apex of the back swing immediately drive your heels into the floor and open your hips to a normal standing position. This is what swings the kettlebell forward, there is absolutely no lifting done with the arms. Let the kettlebell swing only as high as it can with the momentum driven from your hips. Do not try to pull the weight up with your arms or shoulders.
As the kettlebell begins its decent allow it to swing freely behind you. Ideally this should bring you right back to the exact position of your last back swing where you will initiate the next swing.
Make sure that your shins are keeping vertical. If your Knees are driving forward you are likely not leaning forward enough. Your hips are literally pushing on your forearms to drive the weight up. There is a lot of timing and skill required to get the Kettlebell Swing, be patient and work hard.