The model is a grouping mechanism for IDEF0 diagrams. You specify properties such as model viewpoint, purpose, and description for the model. Within the model you build an IDEF0 context diagram, and decompose that diagram with multiple child IDEF0 constraint diagrams.
IDEF0 context diagram
Every IDEF0 Context (or A-0) Diagram must be associated with a model. System Architect forces you to define a Model Name for the diagram when you create it. This is in keeping with the IDEF0 specification.
To provide flexibility in modeling, you are not forced to define a model for non-Context IDEF0 diagrams. You can add one later. When you add a model name later, you can choose either of the following options.