As I expected, the Amazon page is selling the Windows 10 license key, but you still need to download the Windows 10 ISO and create the bootable media to install Windows 10. Generally the Media Creation Tool is the easiest way to do that.
If you are one of the unfortunate few (and I'm among them at the moment) getting an error code when trying to use the Media Creation Tool then this workaround from member Freebooter does work: https://www.bleepingcomputer.com/forums/t/662886/media-creation-tool-error-code-0x80072f76-0x20017/page-2#entry4390003
If you're on DSL it takes at least several hours to download the Windows 10 ISO. It's a bit less if you're on a cable modem and even less if you're on fiber optic.
I always suggest that, rather than using the Media Creation Tool's option to create a bootable USB drive, that one choose to download the ISO instead and either burn it to optical disc (if the machine where you need to install has an optical drive) or to use Rufus or similar to create the bootable USB from the ISO. I've had a failure toward the very end of the process when trying to use the Media Creation Tool to create a bootable USB and had to start from the very beginning, which is very time consuming.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story