flake-newbie - question

[JoeRu]

Hi,
i just started with nixos and flakes especially. I just setup a test system and applied your config. Once in a minimal config and a standard config.
The Things i wonder - where i'm wrong - is

• Home-Manager seems in both version not to be installed or applied. Do i need to add it as as a software anywhere? or what am i using wrong?
• Just i wanted to add https://github.com/nagisa/nixpkg-openhab as a module - so i added the config example as module and refered to it as input module modules/nixos
  openhab = import ./openhab.nix;
  and the example from openhab

    # ...;
    openhab.url = "github:nagisa/nixpkg-openhab";
    openhab.inputs = {
        # In case you alrady depend on `nixpkgs` in your flake, consider having `openhab`
        # “follow” it:
        nixpkgs.follows = "nixpkgs";
        # Similarly, for flake-utils:
        flake-utils.follows = "flake-utils";
    };
};

I'm under the impression that nothing at all where done with it. But thats maybe an issue with my missing understanding of the whole concept.

Just thanks for adding the work and the patience with the beginners here.
Johannes