A:Answer We're assuming that you're asking about the SimpliCam, which is indeed compatible with the Gen 3 system. You'll first want to reset them by pressing the button on the top for 16 seconds, and when you release, they'll reboot into setup mode.
You can then set them up again through the SimpliSafe app like new. Just be sure, when the app asks you, to add the cameras to the same location as your Gen 3 system.