There is no easy transfer for Windows afaik. So unfortunately that would have to done the harder more laborious way.
So are these on the same network? Creating a network share can let you copy the files across, or a USB drive to do a manual copy would be the way to go.
What backup do you have? Do the Windows 10 machines have OneDrive documents? If so are both signed in with the same account that could be used to transfer files across.