• When activating the lever, it will show you a sequence to memorise.
  
• Take your time and when you're ready activate the leaver again.
  
• Sort the orbs according to your memorised sequence and activate the lever again.
  
• If you failed, the statues eyes will glow red while showing the failed sequence.
  
• Pull the lever again, to get a new sequence to memorise.

SPOILER (Hover if you want to know the basic order the orbs need to be placed in)
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It's not difficult at all, but it took me a while to figure out, that the orb-placement just follows left to right and has nothing to do with the position of the statue's hands and arms.
Here's how they correlate (Your colour sequence will be different):