By default Gimbal beacons are configured in Gimbal mode and are designed to work seamlessly with the Gimbal SDK and do not require UUID, major and minor at all. Each beacon is already programmed with a unique factory identifier and the SDK will trigger callbacks for each of your beacons as the phone sees them.
If you do however want to re-program them to Gimbal iBeacons for UUID, Major and Minor . Please refer to Gimbal FAQ to configure Gimbal beacon to iBeacon:
How can I configure my Gimbal beacon to be a Gimbal iBeacon?