Unzip the plugin files, go to the "amzn" folder, and open config.php with your favorite text editor and enter in your license key.
line should look like this (but with your license key)
$zonbuilderlicense = 'zonunlimited-123456123456';
Then upload the "amzn" folder to your /wp-content/plugins/ folder.
Now go to the Plugins page of your WordPress admin panel and click the Activate link next to the new WP Zon Builder listing.