Added some more content

Understanding-CUE.NET-brushes.md

@@ -12,3 +12,9 @@ CUE.NET provides by the default four gradients:
 * [Random-Color-Brush](https://github.com/DarthAffe/CUE.NET/wiki/Random-Color-Brush)
 
 Of course you can always implement [your own brush](https://github.com/DarthAffe/CUE.NET/wiki/Implementing-an-own-brush).
+
+### Using brushes
+Currently there are two ways of using brushes:  
+
+1. Directly apply the brush to any _KeyGroup_ you like (including the keyboard itself). This can be done simply by setting the _Brush_-Property.  
+2. As part of an [effect](https://github.com/DarthAffe/CUE.NET/wiki/Understanding-CUE.NET-effects).