u have to split up your 4 characters.
Then put 1 on the right first plate, it should say "hmm that did something to the right". If it doesnt, start on the other side
Then 1 char on the first plate on the other side. Then put 1 char in sneak mode and put him on the 2nde plate, where u first started. (Note that u have to sneak on the plate when the statue isnt looking, then it shuts down). Then repeat for the fourth and last plate.
And that should do it