Grimrock

I seem to have done every puzzle everyone else has gotten stuck at. checkered room, pillared hall and the little puzzle after the cthulu dude statues to get the ornate key...but I have no idea what to do next. I have an ornate key, and a gold key, but there aren't any doors to use them on. I'm exasperated. i've been wandering around for nearly an hour and I am sick of wasting food. I haven't found the life crystal yet if that helps anyone narrow down where exactly I'm at.

Clear all 3 shelves behind the doors, that should open the way.

thank you...people were calling those pedestals in other posts...had me confused.