In Chapter 23, how did Cole figure out how to be invisible?

From the text:

TO BE INVISIBLE he had to clear his mind. That was the secret. Cole stared up into the darkness. In the cold pond, his mind became almost trancelike. The fish and the beaver had come close until he thought of hurting them. The day he touched the Spirit Bear he had been near death and had completely given up trying to being in control. Being invisible had nothing to do with being seen. Being invisible meant not being sensed or felt.