You can download the application from the official web page. After that, save the file to your computer and launch the installer. After the installation process is complete, activate the product using the serial number (ST-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX-XXXXX) provided in the order confirmation email. If you no longer have the confirmation email or if you didn't receive the serial number, you will need to contact the developer.