Begin modifying a task by right clicking it and then clicking Modify Task.
If you’re interested in the other methods available for accomplishing this, please refer to Modifying Task Details.
In the Modify Task dialog, set a time estimate for the task’s completion using hours, minutes, and seconds. Lastly, click OK to confirm your changes.
If you are interested in being alerted when a task approaches its timing estimate, please refer to Task Alerts.