A new profile does not appear after building

Help
1

I try to define a new profile in the config file:

users.extraUsers.cipher = {
  isNormalUser = true;
  description = "Cipher";
  extraGroups = [ "networkmanager" "wheel"];
  initialPassword = "password";
  packages = with pkgs; [
  ];
};

I build and restart with the new generation. No new users are added to the login screen.
I use X11 & GNOME. Looked in the manual and searched for tutorials, but I still don’t know where the cause of the problem lies (maybe it’s GNOME).

2

I changed extraUsers to just users and specified home directory paths for my new user and old, and it works now.

  users.users.<username> = {
    isNormalUser = true;
    description = "<description>";
    extraGroups = [ "networkmanager" "wheel" ];
    initialPassword = "password";
    home = "/home/<username>";
    packages = with pkgs; [
    ];
  };

I am unexperienced with both NixOS and Linux in general, so I wish the necessity of specifying the home directories (if that was the problem) was mentioned in the manual.
I also can’t find where the difference between users and extraUsers is described.