if you don't understand:
Once you get to the Icy Wilderness world, go up to the penguin that is infront of the blocked door, do his mini-quest and the door should open. Then follow the path until you come to a cutscene showing Spyro getting squashed by a mammoth and Sparx runs (or rather flies) off to hunter, after you save Bentleys home and go through the rest of Huunters side quest you eventually find Spyro, and that is where this video starts, just follow my path and you will find the elder that teaches you the wall kick ability.