Installing Nix
Install Nix by running:
sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --daemon
See also the Nix website for full instructions. You will then need to also enable flakes manually by adding the lines:
experimental-features = nix-command flakes
To ~/.config/nix/nix.conf (for your user) or /etc/nix/nix.conf (globally).
Optionally you can configure the garnix cache if you want to make use of it locally.