Upgrade Win7 To Win10 Using Pre-downloaded Material

Hi.
When Win10 came out, we were advised that we could prepare a PC for Win10 but not actually install it at that time. It could be installed later, at no cost. I followed that advice, but like many, I now want (need) to install Win10, as I am currently using Win7.
Problem is, I can't find any instructions on how to activate (if that's the right word) Win10. I can't remember what I did all those years ago. And I can't seem to find any reference to it.
Any help much appreciated.

 

Have a look over here - watch the video.
https://www.majorgeeks.com/files/details/windows_10.html

Also read this and watch the video.
https://www.majorgeeks.com/content/page/how_to_upgrade_to_windows_10_for_free_in_2020.html

 

Thanks very much, Eldon. I can't see exactly how those links tell me what I did in the past, but it looks like they might get me there. I haven't tried it yet, as I have to find my wife's external hard drive so I can make a backup, and I'm flat out with work at the moment.