Hello John,
Thanks for reaching out.
You would need to download the plugin’s zip file from My Account page. After downloading the zip file, you can install it by uploading it on from Plugins > Add new > Upload plugin.
The license key is to get automatic updates for the plugin. First, you would need to install the WPFactory Helper plugin. Then please navigate to Dashboard > Settings > WPFactory. The Price Offers for WooCommerce Pro plugin should be listed there. Then, go to your My Account page, paste your website URL, and click on the Generate key. After generating the key, paste the key into the WPFactory Helper plugin, and you will start to receive automatic updates.
I hope that helps. If you have any other questions, then please let us know.
Kind regards,
Moshtafizur