Have you gotten the message: "the wheel of time is turning around & around, but you may crack the time that is running out" (or something like that)? Check your "notebook." Inventory + inventory. More hints if needed (selfishly), cuz you'll soon be where I am stuck.
I'm now on top of the mausoleum placing the coloured glass inside the cones. I'm assuming you have to put them in the cones in a particular order and when done place the lantern on the platform. Is this correct?
The correct order for the 4 globes. Start at the front left cone and go clockwise: green, yellow, blue, red. Make also sure, that the latern is on the platform. Go inside the mausoleum and see what happend.