On casual this is super easy, but if you're playing on a higher difficulty let Mhairi do most of the tanking for you. You will be attacked by a Hurlock, Shriek and Ogre. When you're ready enter the gates of Vigil's Keep (Map Location #2).
They will join in and help you fight off the darkspawn in the area. While you're fighting through this area and Vigil's Keep try to help out as many of the soldiers as you can. You can explore this small contained area (Map Location #1) outside of Vigil's Keep looking for loot and killing any darkspawn you might encounter. You eventually realize that Vigil's Keep is under attack from darkspawn. A warden warrior recruit named Mhairi is travelling with you.
This DLC begins with your warden heading to Vigil's Keep to become the new Warden-Commander.