Roles in scrum are Product Owner, Scrum Master, and Scrum Team. A user story should also break down into smaller pieces called tasks. A task seems to have four phases, namely, definition, assignment, implementation, and following.
Who should do what in Scrum about tasks? Is it the responsibility of scrum master to update remaining hours of a task, or is it the responsibility of the developer (scrum team)? Should developers assign tasks to themselves or is it the responsibility of scrum master accompanied by product owner?