Trinket – Use: Teleports the bearer to the footsteps of Illidan’s fortress. (15 Min Cooldown)
This trinket is not that difficult to get however the quest chain is very very long and somehow confusing.
That said there are some good comments in Wowhead where you’ll find all the details for each step.
Also someone posted a script you can copy in the chat window in order to know where you are exactly in the quest chain (in case you’ve started it).