I've heard people suggest starting in a VM (you can always copy your config and keep your changes), but I'm not really a big VM fan so if you have a spare drive or free space you could always dual-boot NixOS and another distro. In the beginning just work on getting a config you like and reading about things on the manual or nixos.wiki. The Nix Pills are cool but more focus on the Nix programming language rather than the NixOS config files, so they're cool to do sometime but not the most important.
I've heard people suggest starting in a VM (you can always copy your config and keep your changes), but I'm not really a big VM fan so if you have a spare drive or free space you could always dual-boot NixOS and another distro. In the beginning just work on getting a config you like and reading about things on the manual or nixos.wiki. The Nix Pills are cool but more focus on the Nix programming language rather than the NixOS config files, so they're cool to do sometime but not the most important.