The Talos Principle 2

This one is easiest done after you have built the bridge to the Tower. Near the middle of the Grasslands Ring map, to the far north, is a blue sprite. You will have ben told to find it if you found the Prometheus site first. Once you touch it, you need to follow it by keeping your eye on it at all times. It will lead you to the Prometheus site and it will go inside. The music continues as long as you don't lose sight of it.