To use the Pro Version of Leo Product Recommendations you need the active license of the plugin. By activating the plugin you will get automatic plugin update and premium support.
When you purchase the plugin you should get an email from LeoCoder with plugin license details. You also can get plugin license information by going to your account.
If you login to your account, under the API Kyes Tab you will get Product Id and Product Order API Key. Those both information we need to activate the license.
Once you complete payment you should get the plugin download link. Or you can download the plugin by going to API Download of your account.
If you install and activate Leo Product Recommendations Pro you should get a License page in your WordPress Dashboard under LPR Setting like bellow screenshot.
Just use the Product ID and API Key in those fields and Click the Active License button.