Not much more to tell. You just need to adjust focus to what looks the sharpest. There is a little leeway in the game here (for once!) so just get it as close as you can and you will probably be right.
So what you should end up with is the 'watermark' symbol overlaying the tusk symbol and the picture focused. Once this is done, note down the position of the four ballbearings.
Take this info to the inside of the tusk that has the corresponding symbol and move the ballbearings there to correspond.
Repeat for the other tusks.