I don't know about a tut but the front brakes are the left side of the image, they are layers from different parts top to bottom. The top right above the black square are the back brakes which are very small. To make to parts of the brakes that you don't want not show you must erase the background and or fiddle with the alphas(which is time consuming and will req more research), and use GGMM to see really what you edited it helps a lot... Hope this helps!