To attach a classifier:
To attach a classifier to an attribute data type, click the Attributes tab, select an attribute in the list, and click the Properties tool to open the attribute property sheet.
To attach a classifier to an operation return type, click the Operations tab, select an operation in the list, and click the Properties tool to open the operation property sheet.
To attach a classifier to an operation parameter data type, click the Operations tab, select an operation in the list, and click the Properties tool to open the operation property sheet. Then click the Parameters tab, select a parameter in the list, and click the Properties tool to open the parameter property sheet