You can start this at checkpoint 14.
- Head right and climb the ladders to the first level
- Head left and rotate the wooden planks (push them towards the ladders)
- Use the lever to raise the planks once rotated
- Climb higher up the ladders so you can now use the planks to jump across up top
- Push the safe off the edge, make sure you're not near when you push it
- Go back down the ladders and into the hole the safe made
- Open the panel on the lower left side in the hole
- Head left inside to the sphere and remove cylinder for the achievement
If you need more help with this you can follow my video guide below which starts at this point: