A catalog stores links to your files and folders you added to it. The catalog only contains the location of your files or folders on your hard drive. The folder, virtual and smart stacks are also stored by the catalog to keep your organization settings.
Create an empty catalog.
Menu: File\New Catalog
Open an existing catalog.
Menu: File\Open Catalog
Save the current catalog.
Menu: File\Save Catalog
Save the current catalog to another name.
Menu: File\Save Catalog As