You must use the Arlo app to connect all your Arlo cameras. If you are connecting an Arlo add-on camera to your account, or if you reached the ‘manually sync’ option during setup, you must manually sync your camera to your SmartHub or base station.
To manually sync Arlo Ultra or Pro 3:
For more information about syncing your Arlo cameras, visit My camera will not sync with the base station; how can I troubleshoot it?.