To build the Guix System (The complete system you would call a GNU/Linux distribution), first, install Guix its self on your existing distribution.
https://guix.gnu.org/manual/en/html_node/Binary-Installation.html It's a bit involved since Guix is a unique program. Then, download the git repository https://git.savannah.gnu.org/git/guix.git cd guix; Then you can build an image for any operating system definition. Start with one of the examples in gnu/system/examples: guix system image -t iso9660 gnu/system/examples/desktop.tmpl
