Normal Mapping in 3D graphics development is the process of using an RGB color-map to create a three-dimensional relief on a two-dimensional plane. The source for the normal map in blender can either be a texture already installed in Blender, or using an external picture-file (.jpg, .jpeg, .bmp, and so on) and loading it as a normal map.
As an alternative to using the Texture Channels, Blender includes a node-based texture generation system which enables you to create textures by combining colors, patterns and other textures in much the same way that you combine Material Nodes.
Here is another Blender Tutorial on adding multiple colors to one object in blender. It's a little quite, so you might have to turn up your volume. Enjoy.