The top-down approach is used to plan at the high level first and then to gradually move to the lower levels of hierarchy. The parent task determines the earliest start and latest finish dates of the children.
Tasks will behave according to the following rules:
Parent in "auto top-down" puts boundaries on it's children start and end dates i.e.: a. start date of any child >= start date of the parent b. end date of any child <= end date of the parent
Parent can be scheduled to start on a non-working day.
To learn about other task modes go to the Task modes page.