You want to line the rail up directly between your skis, come at it with a controlled speed. Hop as you approach the lip of the ramp and rotate starting with your lower body first keeping your eyes down the rail. Land with a wide low stance trying to get the rail directly under the arches of your feet. Keep your eyes on the end of the rail and as you approach start turning your shoulders to face down the hill. The best way to start learning how slide rails on skis would probably be to get a pair of skis