Hi George
You cannot downgrade a Windows 10 version the Enterprise to Home, the only option is to backup your data, clean install the Windows 10 Home version, then re-install all your applications, Microsoft provide us no other way to go from Enterprise or Pro to the Home version . . .
The Windows 10 Home (Download) you are purchasing means you need to create your own Windows 10 USB, there should also be another option, where they will send you on an official Windows 10 USB . . .
How to create a Windows 10 USB:
Click this link:
https://www.microsoft.com/en-us/software-downlo...
to download the Media Creation Tool (Click on Download Tool Now), with that you can download the latest Windows 10 ISO (Select Create Installation Media for Another PC), you can create a bootable USB flash drive (min 8GB) using that tool