On this page of the Assassin's Creed Valhalla guide, you will find a detailed walkthrough of the Jotunheim side quest Aegir's Daughters.
Reward for completing the mission: 1200 XP.
At the location marked in the image above, you will meet several female Jotuns, daughters of Aegir. They are very welcoming and happy to answer your questions about Jotunheim.
This task's first stage is straightforward - listen to what the women have to say and drink with them three times.
After a while, you will wake up on the upper floor of the feast hall. Go downstairs and then go outside to check the traces of your drunken escapade. First go to the big wooden cauldron with mead. When you climb up, you will notice that there is a shattered boat floating in it.
On the left, on the roof of one of the buildings, you will find a broken wooden wagon - this is the second clue to investigate.
Near the Feast Hall, you will come across a boar released during the night and is now running loose in the settlement. Defeat him and the mission will end.