Hit the "Get license" button on the 'Free trial' pop up window (this is automatically displayed once the Spellproof app is downloaded and installed)
You will be redirected to "My Atlassian" page to get a New Trial License
Enter your Organization's name, and agree to the Terms of Use
Hit the "Generate License" button
Your trial license will now be generated
Hit the "Apply License" button on the "Apply Your License" pop up window
You will be redirected to the "Manage Apps" page and the trial license will be applied
Once applied, the 'Licensed and ready to go!' pop up window will be displayed