Flake Error: Does Not Provide Attribute 'activationPackage'

I’m new to Nix and attempting to configure Home Manager via a Flake, however, currently encountering the following error:

error: flake ‘git+file:///Users/danke/dotfiles?dir=nixpkgs%2f.config%2fnixpkgs&shallow=1’ does not provide attribute ‘packages.aarch64-darwin.homeConfigurations.danke.activationPackage’, ‘legacyPackages.aarch64-darwin.homeConfigurations.danke.activationPackage’ or ‘homeConfigurations.danke.activationPackage’

The system on which I’m attempting this configuration is an M1 macbook with MacOS Monterey using Nix version 2.10.3. I was under the impression by executing the following command home-manager would be installed, the flake would be built (using the activationPackage provided by homeManagerConfiguration), and the configuration would be ready for activation:

nix build --impure --no-link .#homeConfigurations."$USER".activationPackage

I would appreciate help in understanding and resolving this error. Below is the flake.nix file used in the configuration. Thanks!

# Flake-based Home Manager: https://nix-community.github.io/home-manager/index.html#ch-nix-flakes
    description = "Home Manager Configuration";

    inputs = {
        nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
        home-manager = {
            url = "github:nix-community/home-manager";
            inputs.nixpkgs.follows = "nixpkgs";

    outputs = { nixpkgs, home-manager, ... }: {
        homeConfigurations = {
            "danke" = home-manager.lib.homeManagerConfiguration {
                pkgs = import nixpkgs {
                  config = { allowUnfree = true; };
                  system = "aarch64-darwin";
                modules = [
                        home = {
                            username = "danke";
                            homeDirectory = "/Users/danke";
                            stateVersion = "22.11";

pkgs probably needs to be done like pkgs = nixpkgs.legacyPackages.${system};

What do you mean by “needs to be done like”? Is that a technical term?

You cannot import flakes like channels, you need to access the right output for your architecture