For more information about shading network libraries, see View the Shader Library Gallery.
To assign a shading group from the Shader Library
By default, the material type for the shading networks is PhongE. To achieve different results, you may want to change the Material type (by selecting a new Type in the material's Attribute Editor). When you do this, however, some of the material attributes change which requires you to manually reconnect some parts of the network.