Hi Giovanni,
I believe that you have got a purchase receipt email. From there you can download the pro version and please install it. After that please deactivate the lite version and activate the pro version. You will have section there to keep the license key and should have all the features of Pro version.
For details, you can check this installation video. https://www.youtube.com/watch?v=EHrV2XzSd1k
Hope this helps.
Thanks