Mepland
As the letter says, there are 4 pedestals. There is also a note lying on the ground that says:
These are the 4 pedestals.
On the first pedestal, you must place the blue gem
On the second pedestal, you must place the yellow gem
On the third pedestal, you must place the green gem
On the fourth pedestal, you must place the red gem
These are the 4 pedestals.
On the first pedestal, you must place the blue gem
On the second pedestal, you must place the yellow gem
On the third pedestal, you must place the green gem
On the fourth pedestal, you must place the red gem