Only members of the Site-Admin Group can add Paid Add-ons or Applications to the instance
Install Plugin
To find new apps, navigate to Jira Settings > Apps > Find new apps
Search for Three Dimensional Date Gadgets Cloud
Click on Try it free > Start free trial (The app will start installing)
Wait for the "Success, Three Dimensional Date Gadget was added." message appears in the top right
Click on Manage apps > Free trial (for Three Dimensional Date Gadgets Cloud)
The trial license will be applied automatically. You are now subscribed to the app