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.
A project is a temporary endeavor designed to produce a unique product, service or result with a defined beginning and end (usually time-constrained, and often constrained by funding or deliverables) undertaken to meet unique goals and objectives, typically to bring about beneficial change or added value.