1. Defeat Tugar Bloodtotem. Speak with War Councilor Victoria, she will teleport you to Navarrogg to begin.
2. Unlock a new appearance for your artifact weapon.
3. You need to provide your account.
4. Your character's item level should be 910+.
5. ETA: 1-3 Weeks.

Tips: Only if Mage Tower is active within three days, you can get the Artifact Challenge Quest. After done, then you can unlock a new Artifact Challenges Appearance.