After you've gone to the platform and pulled the lever on the left, experiment with the remaining controls and take note of what they do.
It looks like some of the levers change a variable of the experiment, and one lever conducts it.
The three levers that you can slide change position of the fulcrum of the lever; the lever that you pull creates a ball from the top of the center building. Also, if you zoom in on the orange-ish ball to the right of the lever, you'll see the other side of the ball that you may have seen after going up the red elevator. You should see that up close, the four sections of the side are all brown. You should now be able to determine the balls exact weight; if you didn't see the weights in J'nanin's main tusk, you either need to use the trial and error method, or you can go back to J'nanin via the linking book near the entrance to the age. Although you now know how to work this contraption, you'll have to find another variable of the lever to change.
I'd like more information on all the levers
Where do I go from the platform, as I can't seem to do anything here right now?