Well i kind of struggled with this puzzle on my first playtrough too, but its kind of easy once you figure it out.
You are supposed to weigh the sphere's to find out which is the heaviest and which is the lightest . Then you are supposed to order after their weight.
Or you can just pick them up and they will order them selfs correctly in your inventory and only need to place them down from left to right.
by the second one you need to touch the white Symbol on the bottom left again to solve the puzzle.