crum requires that at the end of each sprint that you deliver a potentially shippable product increment. To maximize the ability of the team to deliver this functionality, it is important to break this functionality into managable chunks.

During sprint planning, the team creates its sprint backlog containing tasks necessary for the team to meet their commitment in fulfilling each product backlog item as part of it sprint goal. I have seen team members stuggle with determining how to define tasks in a way that will support Agile and Scrum values.