On this page of the Assassin's Creed Valhalla guide, you will find a detailed walkthrough of the Food of the Gods side quest in the Asgard region.
Reward for completing the mission: 1200 XP.
In the place marked on the image above, you will meet Andhrimnir, who wants to organize a hunt for the Immortal Boar.
Go with him and a few other warriors into the forest to hunt this legendary beast. Once you hunt the boar, the mission will end.