This page of the Assassin's Creed Valhalla guide has a detailed walkthrough of The Infinite Noise of Men side quest.
Rewards: 1,200 XP.
In the place marked in the picture above you will meet two arguing men – Alduini and Sebbi.
When you join the conversation, one of the men will ask you which one of them deserves a greater share of the profits from their business. You can choose any answer because you won't be able to stop their argument anyway.
Talk to the children at Sebbi's house – you will learn that once men worked together and shared their profits equally. The problem arose when the silo built on the farm.
Go home and talk to Sebbi. The choice of the dialogue option doesn't matter – the men will fight anyway.
Pull out a torch and then throw it at the silo. When the farm starts burning, talk to the children to complete this task.