To connect to your Gogo device, open your iPad's SETTINGS APP and select the WI-FI line. If your Gogo device is powered on, you should see the network available to connect to. Once connected, you can confirm that the device is available for use with ForeFlight by opening the ForeFlight app and going to MORE > DEVICES. You will see a tile for the connected Gogo device.
Please ensure that you are running at least ForeFlight version 11.2 or later, and your Gogo device is on software version 2.7.