Ashley was lost for a brief moment, unsure what she was supposed to do next, until Persephone hissed more directions for her. Apparently, the arch was a portal to Gryffindor Castle, the place where Hades was most likely residing at. Ashley was incredibly relieved to hear that there was another mode of transportation available for her because there was no way she'd be able to apparate or make another portkey. But then, Persephone helpfully reminded that the portal had yet to be activated and to do that, the arch had to be filled with a certain amount of magic. That was, of course, what the pedestal was for.