I wont lie these tricks are better taught in person on snow or a trampoline. But for a backside cork 5. Leave your toe edge throw your shoulders up into the air off the lip. Then twist into your backside spin while dipping your right shoulder toward your back foot. Great time to grab mute. This will send your body off axis and the board out in front of you. Your head should be glued to your left shoulder until you spot you're landing just before you come around 360. At this same time your board will be dropping back underneath you. Time to spot the landing let go of the grab and put them feet back down. It helps if you land toe edge first giving you the chance to land and skid a little if you don't put the board down perfect. Remember stomp you're landing don't just let the board touch the ground. Let me know if any of this is hard to understand I can try and explain further.GL
If you have a chance to work on a trampoline first take it!!