Thanks for your purchase on Windows.
The Pro version needs to be purchased separately per platform, as noted in the app store description, the purchase page on Android. It's also explained in detail here in the FAQs.
To purchase the Pro version on Android, you can use the "Pro version" menu item in the main menu (accessible using the "menu" button on the top left). Or, whenever you try to access a Pro feature while the app is in "free" mode (e.g. after the 7 day trial period), the app will show a dialog, offering you to go to the purchase screen.
