In order to active theme license of a premium theme, you need to install and activate premium theme first. Refer to your theme documentation page for step-by-step guide on how to install and activate a premium theme. Here is an example.
Step-by-step guide to activate the theme license
1. Go to Appearance > Theme License (Premium theme must be activated)
2. Enter your license key and click on Save Changes. The page will reload. (The license key is sent in the purchase receipt email. You can also find your theme license key from your profile on Blossom Themes.)
3. Click on Activate License and your theme license will be activated.