Thank you for your reply! If the "blue stone" you are talking about is the pedestal in the first room, then it is a charging pedestal you are talking about. The lantern can run out of energy, so in order to recharge it you should put it on that stone. The actual point of the game though is to solve the light puzzle, rotate the crystals in a way so the light travels through all of them. But the line renderer is buggy and for some reason doesn't show sometimes