Same way gravestones work, you click them and text appears above them.
When looking at the origin files, there is a script attached called GEN_itemdialog (ssomthing like that), and inside that is a place to put a dialog file.
that alone doesn't work.
the on-use has a send script to osiris. but I cant find anything in the entire story script that references the dialog file.
So how do you get this to work?
Getting rid of the script attached to the gravestones doesn't even break the object, it still displays the general gravestone text over it. so it almost seems like that part isn't even needed.