If you don't know what a wheel barrel is it's a royale foot in the back and the front foot rolling on the back wheel. If you want to get a wheel barrel you first need to learn a royale and probably a backslide, it is also recommend to be able to do a heel heel on flat ground. Starting out you might want to try the stall it's a little hard because of the wheel but really all you have to do is lean forward some. Once you got the stall you try the grind. The angle that I come at it is somewhat weird I come at it almost like a soul and I just jump up landing on my back foot royale'n, while I bring my front foot down on the wheel, The front foot isn't even really there for support only to keep you up if you would start to fall foward.