redsleeve.org and rel 8?

[Robert Moskowitz]

The homepage only points to rel 7.1 and 6.  No link to 8.

I found the images at:

https://www.mirrorservice.org/sites/ftp.redsleeve.org/pub/el8/

I see
https://www.mirrorservice.org/sites/ftp.redsleeve.org/pub/el8/8.2/rootfs/rsel8_root_img.tar.gz

But what do I do with it?  No instructions.  How do I put this onto a
mSD and HD?

For Odroid HC1, I would then add the uboot I am using for Centos7, make
changes I have to extlinux.conf and see how it goes...

thanks