After activating the plugin, you need to enter the License Key. The license key can be copied from the purchase confirmation page.
To know more about Install & Activate, Click Here
The screenshot below shows where the license key exists.
After copying, go to Wish List >> License >> License Key.
Paste the License Key in the preferred text box and click on the Activate button.
In the refreshed window, you can see the status is changed to Active.