This is the most simple of all grinding tricks and the best introduction to the technique and feeling of grinding. You need a clean ollie for this one so that you can get on top of your chosen obstacle - so perfect your ollie first and then make sure to pick a ledge that isn’t too high to start with. Once you’ve mastered this one, you can move onto all the other grinding tricks, so learn how to 50-50 as the building block for the rest of your progression.