This quick reference guide covers the basics on creating, changing and executing the CATT scripts in various modes. The front page is divided in three sections that descibes the Main menu icon functionality. The second section describes the how to maintain a script and the various screen components. The last section simple explains the CATT line item editing commands and the available function codes that can be used in enhancing your scripts. On the second page the concepts of import, export and variables are discussed and how they are created and used to make CATT model/procedures more modular. In addtion, the CATT execution screen is descibed which includes processing modes, log types, import parameters and variants.