I think this is the key point......
Please be aware that you cannot use the free upgrade offer to perform a clean install on first attempt. You must first upgrade from the qualifying version of Windows 7 or Windows 8/8.1 (whether you do it through Windows Update or using the .ISO file). Ensure the upgrade is completed successfully and then ensure that it is activated. You can then proceed to do a clean install by using recovery media or using the Reset function in Start > Settings > Update & Security > Recovery > Reset this PC (Get Started).
I, too, am going to wait a bit. My wife's new laptop came with Win 10 so I have an install to get familiar with.