Download the free trial or purchase the extension. From this point, from this point, locate the .trex file on your computer and open it using Tableau. After placing it in desired dashboard(s), new users will be required to sign up first. After logging in, you will be able to use the extension within your Tableau dashboard(s).
For more information on how to add Tableau extensions into dashboard(s), please visit the following link: https://tableau.github.io/extensions-api/docs/trex_getstarted.html