Enterprise versus project data
If you come from a background where you work with projects individually, the concept "enterprise" may seem foreign. Simply put, "enterprise" means information that is shared across all projects. For example, people are resources in P6 and resources are defined at the enterprise level. While an individual may work on only one project, they may be assigned to other projects as well. So having them at the enterprise level allows you to allocate people across projects.
Another quite different example of enterprise data is screen layouts. These are customizations of the various screens in P6, such as the view of activities in a Gantt chart. Layouts can be stored and shared globally, so are enterprise data.
Project data, in contrast, is limited to a single project. An activity, for example, belongs to one and only one project. Likewise, project work and reference documents are specific to projects.
However, some data can be stored either at the enterprise level, or...