Speak to Brytthel again and she'll direct you to the city. Note that the faction boost from the quest you just completed will make the guards non-aggressive. You don't actually have to put on the signet ring.
Enter Maldura at 259.05,150.95,481.62 and find Brumley Langboom at -83.37,13.33,193.41 .
Take the scanning device back to the tunnel where you found Brytthel. Place it at the entrance on the glowing spot.