To make use of the sunrise and sunset relative times at Cam actions, the camera's latitude and longitude must be set. Check with your local weather service to get these coordinates.
If there is an already-set up camera, its latitude and longitude are automatically used here if this is not already set. You still needed to do a Save of the auto-set values. If you make it to Test-Join without Saving here, you will be instructed to come back here and Save. This applies to any Cam setup panel with unsaved fields.