Overview
There are two ways to specify 3Delight materials in your recipe: using Katana's Material node, and using Katana's Network Material node. The main difference between both is that you may define a whole shading network based on a Network Material, while a Material node may only specify a sole shader.
Using the Material Node
3Delight shaders can be added to a Material node by clicking Add Shader, and then by choosing the desired shader type under dl in the option menu. This will add a dlShader group of the specified shader type. That that contains an option menu; this option menu can be used to select the desired shader. Only OSL shaders of the specified type will be shown. Picking one shader will populate the dlShader group with its attributes.
Using the Network Material Node
In order to connect 3Delight shaders to a Network Material node, it must have the proper ports. Adding ports is done by clicking on Add Terminal, then choosing the desired shader type under the dl section in the option menu. The Network Material can now receive an incoming connection from a DlShading Node of the appropriate type.