Gandyx has been build on top of Alteryx. To be able to use it, you have to download and install Alteryx Designer first. Alteryx offers a free trial version which has full functionality and can be used for 30 days. It can be downloaded from the Alteryx website.
After installation of Alteryx, install the Gandyx macros. An installation package can be found here. A trial-license-file with instructions will be send separately via email.