Using 7zip for extracting the downloaded .tar.gz does not work. I ran into this issue myself and found a thread by someone who had the same problem: Topic:Vp73pxywm362a3t5 Using the tar command that was brought over to Windows 10 a few releases ago did work, though. This download help page should be updated accordingly.
Topic on Talk:Download/Archive 2
thanks @Itschotsch!
btw, tar is on board since Windows 10 build 17063 [1] (so since 21 Dec 2017[2])
[1]: https://www.addictivetips.com/windows-tips/use-tar-on-windows-10/
[2]: https://www.windowscentral.com/windows-10-build-17063-pc-everything-you-need-know
Thank you for this comment, I came here to do the same.
It's disappointing to discover that no action has yet been taken on something so fundamental.
I have wasted two days trusting the instructions as they stand.