Basically, a switch straight air, take off switch, land switch, no rotation. They're difficult and risky because your basically blind te entire time in the air, and theres no way to spot the landing.
Learn how to take off switch on smaller jumps first, stick to doing 180's so you can see your landing. Start zero'ing small stuff, then move up to switch 1's off larger features to get the feel of when to pop and how to pop when switch. Once you're good and comfy there, man up and try it. Throw in a shifty or kang for stlye points.