This video guide for The Talos Principle will show you how to complete the puzzle from World C called “Cemetery”.
For anyone who got stuck not being able to get the beam to open the first gate where the 2 balls were moving back and forth, I feel you. I got stuck here for a long time too. I don’t think I had really done much with those white spheres yet so it was a weird one to get your head around. Hopefully the video guide below for the Cemetery level makes it a little easier to figure out.