A section is a cut through the 3d-model. An elevation is different. It shows the face of something, or perhaps more correct, the projection of an object/s to a plane.
Project Definition: Establishing Scope, Vision and Work Effort. In order to have any realistic shot at a successful project, (delivered on time and on budget) the overall vision and work effort must first be fully defined --- i.e. broken down into small, manageable and actionable parts.
Project Description is a formally written declaration of the project and its idea and context to explain the goals and objectives to be reached, the business need and problem to be addressed, potentials pitfalls and challenges, approaches and execution methods, resource estimates, people and organizations involved, and other relevant information ...