Since we are moving very fast and releasing the product several times a week, we try to break the user stories into small components — subtasks. The responsibility for this lies entirely on the members of the team. We use Jira to do this, which…
The Product Owner handles maintaining detailed user stories. They should not contain all the small details but only illuminate the necessary functionality. Also, there should not be a solution in the stories, because it lies entirely on the team. The purpose of user stories is to understand what we are doing, for whom and why. Usually, user stories are highlighted in a Google Doc and later transferred to Jira, in order for the team to check and break them into tasks.