You must create a pattern instance as the first part of applying a pattern to your model design. Patterns always originate in the Pattern Explorer view. You can drag the pattern to a UML 2.0 model or to a model's class diagram or freeform diagram.
If you drag a pattern to a diagram of a model, a pattern instance is created in both the model on the diagram. Using the Apply Pattern wizard is another, more structured, option to apply patterns and it creates the pattern instance in the UML 2.0 model. You can create multiple concurrent instances of the same pattern.
You can only drag a pattern to elements that can own the type of pattern you are applying (collaboration, class, or package pattern).
To create a pattern instance, do one of the following steps: