A key concept of Agile is to timebox. I usually refer it as the “Divide and Conquer”. Scope and requirments comes hand in hand in shaping on what can be done by the end of timebox. Although Scrum timebox daily, the reality is not true of that.

What to Divide
The rule of thumb in dividing the tasks is to find the easiest component. Completing the easy component leads to clarify. Once completed, you can further determine if the task can be split further. So, how do you identify the easy component? Easy usually refers to below criterions:
- It is known solution and you can complete easily within an hour.
- The task component have low risk.
- You can reuse the task component.
Conquer After Divided
After you divide your tasks, it is ready to be completed within the timebox. Some of the divided task may be added back to the backlog as it will exceed the timebox. You shall take many iterations to improve on your timeboxing. One key things you learn is the ease of completing your tasks after you divided it in the most effective way.