What Makes Up a Work Breakdown Structure (WBS)? 
The main objectives of the WBS are to split the project into manageable units, define basic dates, and determine its costs.
The WBS divides the project step-by-step into structure elements. The elements are called work breakdown structure elements (WBS elements) in the Project System.
You can structure the WBS from various viewpoints:

Creating WBS Elements
Creating Project Definitions
Project Profiles
Status Management
Subprojects