Before you can use the Catalog API to perform certain task, you will have to create a Designer object and then get a Catalog API instance.
To create a Designer object, use the constructor Designer(String path, String name, DesignerUserInfo user) in the Designer API. The constructor has two parameters, the catalog path and catalog name. The catalog name can be the name of an existing catalog when you want to open a catalog, or the name of a new catalog when you want to create a catalog.
To get a Catalog API instance, use the method getCatalogAPI() in the Designer API.