Windows 10 install using bootcamp assistant on MacBook Pro 2020

1) I created Windows-10 ISO image on USB flash drive from Microsoft website using their download tool on a Windows-10 Pro machine running 64 bit Windows. When I insert it in Mac in Bootcamp Assistant says "Remove External Storage" and won't proceed unless this is done. So I disconnected USB flash drive and continued.

2) On next screen Bootcamp Assistant asks for ISO image and partition info. I connected the USB flash drive that has the Windows-10 ISO image files. What's the folder / filename to be selected for ISO image? Whichever one I select, Bootcamp Assistant gives me a dialog box saying "Need 64 bit Windows 10 or later ...". What is this? I can't proceed with disk partitioning and Windows-10 setup. How do I proceed?