Light the 24 Torches of Forewarning in sequence, starting with the first torch at Darklight Wood zone point, following the road from Darklight Wood to the last torch at the J'Rais Bridge (the Commonlands station). Keep in mind the following:
The quest description may indicate that this is a timed run, but this is no longer true.
When you get near each torch, a message will appear on your screen saying that you have approached a torch of forwarning. It may take a moment for the message to appear, so consider running in a circle around the torch if there appears to be a delay.
The 24 torches appear in order on or near the path you will be running. You won't need to backtrack unless you miss a torch. Pay attention to the messages to ensure you're lighting them in order.
Although the quest says you are lighting the torches, visually they are now always lit (since the rediscovery of Neriak, City of Hate).
Kill the three mobs below in the order listed.
Slay Warlord T'Velk ( -233, 7, -650 ) /waypoint -233, 7.25, -650, a 29 heroic ghost who will spawn and attack you on the D'Abth Bridge when you cross.