When defining the breakdown of a project with Summary Tasks and Tasks in the WBS Chart view, we often see this done incorrectly. Here is a quick lesson on how to properly structure your project.

In a WBS View that displays Tasks horizontally under their respective Summary Task, do it this way:
Or, in a WBS View where Tasks are displayed vertically under their respective Summary Task, do it this way:
In each of the above examples, Task 1, Task 2 and Task 3 are subordinates to the Summary Task box and will properly roll up information.

Avoid doing it this way:
In this example, Task 3 is a subordinate to Task 2 and Task 2 is a subordinate to Task 1. Both Task 1 and Task 2 are Summary Tasks in this example . You will get improper roll up of data with this approach since the only real Task is Task 3. 

To ensure your WBS Chart is properly structured make note of the currently selected Summary Task or Task when using the Insert commands.
Insert Task After adds a Task to the right of the selected Task if your tasks are displayed horizontally and below if you are listing the tasks vertically under their Summary Task.

Insert Summary Task creates a Summary Task above the currently selected Task.

Insert Subtask creates a Subordinate Task to the currently selected item.

You can also use the keyboard shortcuts listed in this form to quickly add new items in your WBS Chart.