Make sure to learn how to nose butter on the slopes first. This way you will avoid unnecessary frustration. www.stompittutorials.com/tutorials/how-to-butter-on-skis/
Start out practising the movement while standing still. Lean forwards with a lot of force on your chins and your hands on or next to the noses.
Find nice flat(ish) area to first start practising the movements. It is good if the area is a bit shaped like a roller.
Start out winding up the rotation
Tilt your body into the turn and up the hill
Here you will have a ton of chin pressure so keep the back of your legs strong to not over extend your knees
As you in this case turn to the left you will have to wind up rotation in the opposite direction.
As I set the rotation off I tilt the body down and into the turn. I also let the hand drag in the snow
Try to keep the leggs close together and really shove the noses into the snow
At this position make sure to maintain this awkward movement and force those skis into the snow using the chins and your strong hamstring muscles on the back of your legs
At the end of the butter you will have a fraction of a second to get those tails underneath yourself in order to ride away like a boss.