The Metamodel group enables you to create metamodel diagrams with support for MOF diagrams.
A Package is a namespace as well as an element that can be contained in other package's namespaces.
A Class is a representation of objects, that reflects their structure and behavior within the system.
An Enumeration is a Class with an enumeration stereotype.
A Primitive supports the MOF specification (deprecated - use the UML Primitive in the Class group).
To add an element to the current diagram, click on the required icon and drag it into position on the diagram. Set an element name and other properties as prompted.
To add a relationship, click on the required icon, then click on the start element in the diagram and drag to the end element.