On this page of the Assassin's Creed Valhalla guide, you will find a detailed walkthrough of the Art-Scop side quest.
Reward for completing the mission: 1200 XP.
Go to the place marked in the picture above you will meet a bard. The man immediately recognizes Eivor and starts singing about him.
The bard will offer you a deal - in exchange for a fee, he will immortalize Eivor's deeds in a song. Pay him and then listen to the song to complete this task.
If you want, you can later sneak up to the bard from behind and steal the silver you gave him earlier.