How to update Lightroom 5.2 to 5.7.1

There have many posts about "How to update Lightroom 5.2 to 5.7.1"  all links provided are out date or do not work.  I moved to a clean version of Windows 10. Installed Lightroom and want to update to latest version 5.7.1.  How do I obtain updates?  My account shows I am a registered user but is not listed in "order history" for the product was purchased in the retail channel.

{Moved from Lightroom Cloud to Lightroom Classic Forum by Moderator}