The Jagged Crown is the second quest you will undertake in both the Imperial and the Stormcloak questlines. After accepting the quest from General Tullius or Ulfric Stormcloak, talk to his assistant, Legate Rikke for the legion or Galmar for the Stormcloaks. Whichever one it is will tell you to meet them outside of Korvanjund.
If you are undertaking this quest for the Imperial Legion, upon your arrival at Kovanjund you will meet up with a small group of your fellow Imperial soldiers led by Legate Rikke and Hadvar. Go inside and defeat the band of Stormcloak rebels.
If you are undertaking this quest for the Stormcloaks, upon your arrival at Kovanjund you will meet up with a small group of your fellow Stormcloak rebels led by Galmar Stone-Fist and Ralof. Go inside and defeat the awaiting Imperial Legion soldiers.
The quest converges at a Nordic puzzle door which requires a code carved into the Ebony Claw artifact, which is found right in front of the door. The symbol code for the door is on the palm of the Ebony claw: fox, moth, dragon.
The party progresses through the door and encounters a barred doorway which requres a lever to open. It can be found by taking a passageway to the right of the room (when facing towards the barred door) and continuing over two walkways to a chest. After stepping off the wooden walkway, turn to face left and you will see a handle in the wall beside a brial urn. Pull this to open the doorway.
NOTE: on the way to open the barred door you pass an altar on the second level that has a dagger lying on it, if you remove the dagger, a passageway opens up that leads to another secret entrance that is opened by a lever to its left. Inside is a chest with leveled loot. The chest is booby trapped, so stand to the right of it as you open it.
Entering the room past the barred doorway, you will see a Draugr inactive sitting on a chair. Interacting with it will wake it and, of course, it will be hostile to you. Try to approach the Draugr and attack while in sneak mode as the damage multiplyer will often kill it with that one hit. It will usually raise three other Draugr to assist in attacking you. After defeating them you are free to retrieve the Jagged Crown.
IMPORTANT: After you have the Jagged Crown, move further down the cave to find a Word Wall from which you can learn one of the words for the ‘Slow Time’ Dragon Shout.
Take the Jagged Crown back to General Tullius at Castle Dour in Solitude or Ulfric at the Palace of the Kings in Windhelm, depending on which of the two sides you’re undertaking this quest for. You are then instructed to get new orders from their assistant.