Easy. It works exactly the same as for any other Philips Hue light. Just open the Philips Hue app and go to 'Settings' > 'Light setup' > 'Add lights' and follow onscreen instructions.
Note: the Hue go can only be “discovered” by the Philips Hue app once. To add a Hue go that has already been discovered just go to 'Settings' > 'Lights setup' > 'Add lights' > '+ Add serail number' and follow the onscreen instructions.