After the opening cinematic, you'll find yourself in the Main Hall. Take a moment to familiarize yourself with the controls. Head straight and examine the large double doors. They are locked. Turn around and head towards the camera. You'll find a door on your left. Enter it.
This leads to the Dining Room. Immediately to your left, you'll see a door. Ignore it for now. Proceed further into the dining room. On the far side, you'll find a Green Herb on the floor near the fireplace. Pick it up. Green Herbs restore a small amount of health. Combine three Green Herbs to create a Full Heal. Continue to the back of the room and exit through the door.