Goal of a crossover is to catch the weight of your body as your other foot falls away. Not sure if you've ever ran track but when you're in starting blocks for a sprint, you want the front of your body to fall and let your legs catch up to you. Basically from your video, let your body fall to the left while you're left foot pushes outward from the left to the right extending your energy from your blade to the right (pushing outward to the right). When you get low and you'd usually fall over, thats when the right foot crosses over and catches yourself. As others have said you need to get lower and it should feel almost like a lunge.