Use the B-button or any switch key that is connected to I1-I4 inputs (that controls R, G, B, and W channels respectively) if you want to include Fibaro RGBW Controller into Z-Wave network.
Also, there is an auto inclusion function in this device which lets you include the device into the Z-Wave network automatically and all you have to do is to connect the voltage supply.
Before you go ahead with the inclusion you would have to make sure that the Fibaro RGBW Controller is not connected to the voltage supply. Also, you would have to keep the controller within the direct range of the main controller.
Then the Z-Wave network main controller should be put in learning mode.
After that you would have to connect the voltage supply. This auto-includes Fibaro RGBW Controller.