How to: nixpkgs derivation!

[aspauldingcode]

fork nixpkgs
clone forked nixpkgs
edit local repo under nixpkgs/pkgs/by-name/so/some-package/package.nix

https://github.com/aspauldingcode/nixpkgs/blob/master/pkgs/by-name/README.md

anyway once you have correctly built this (with nix-build -A <pkgname> or nix build -f . <pkgname>), you will have a binary in result that you can run to make sure it runs

Then you can open a PR request.