You use the Attribute Dimensions tab to create attribute dimensions:
In the Name box, you enter a name for the dimension. You follow the naming rules for standard dimensions. See the Oracle Essbase Database Administrator's Guide.
In the Type box, you select a type (text, numeric, Boolean, or date).
You click the New button (to create the specified dimension) or Delete (to delete the selected dimension).
“Building Attribute Dimensions and Associating Attributes” in the Oracle Essbase Database Administrator's Guide