1) When first learning, try it off a knoll, roller, or jump knuckle (make sure your not going to be in the way with the last one)
2) Go at moderately fast pace, it makes it easier to pop
3) Swing your arms across your body (in a downward diagonal motion - so if your going to spin left swing from your right shoulder down to you left hip)
4) As your arms cross your body lean as far forward as possible (it's scary at first, but no worries your wont land on your face)
5) Look over your shoulder and keep spinning (3, 5, ect.) then spot your landing and stomp it.
This is all easier with softer skis obviously (The skis in the video look a bit like Anthems, which a very soft), but can still be done with stiffer skis, you just need to throw it harder and lean more.
Hope that helps.