Dragon Age: Inquisition just saw the release of its first DLC, Jaws of Hakkon, which is out now for both the PC and Xbox One with the PlayStation 4 undoubtedly to follow.
Getting to the DLC content isn't as straightforward as say, loading it up from a list of campaigns. Instead, you'll have to have a pre-existing saved game going in order to access the new content. You're suggested to have a party of level 20 characters to experience the new content, unless you want to die a lot.
When you load up your save with the DLC installed, you'll be alerted to a new active quest set in the add-on's new Frostback Basin area.
To get there, you'll need to head on over to the War Table in Skyhold and check out a new quest marker called Investigate Frostback Basin.
You'll need to spend 8 power. Be sure to read the description of the quest, which says an Orlesian professor intends to work with the Inquisition to discover ancient relics that may be of aid in your campaign against Corypheus.
Accepting the mission will complete it immediately and take you to a new area, where you're greeted by Scout Harding, who is flanked by the professor. The professor will set you on a quest to discover what happened to the previous Inquisitor, and off you go!
The following video contains a glimpse of Frostback Basin.