Hi,
To subscribe to the Pro version, you can click on the Purchase button on that page. You’ll be able to view controls, send support questions, and more from within your wordpress install. You can also go through the merchant’s site at Freemius.com to cancel your subscription at anytime.
If you have any further questions about the Pro version, please contact me at [email protected]. I’m marking this as resolved here because this forum is for the Free version only.