Create a bottom up tutorial on Nix

[Guisanpea]

Is your feature request related to a problem? Please describe.
I have been through the last days trying to understand Nix better. Concretely, what I have been trying to achieve is to make i3-gnome work After an attempt of tying to do it in the past.

I feel that there are a lot of concepts that I don't really fully grasp.
Why does nix need a /nix/store path
What is the purpose of the Nix DB?
How does a derivation really work?
What does support NixOS /etc/nixos/configuration.nix and makes it work?

I expected the How Nix works guide to teach me all this stuff, but I feel that more than showing how it works it teaches me the principles behind me and how it works

Describe the solution you'd like
I would like to have a guide that teaches Nix from first principles so that every concept that is seen can be understood by its own or by using previously seen lessons

Describe alternatives you've considered
The alternative I have used is to go through several videos/pages that explain all that concepts and trimming the manuals and wiki until I get more or less how everything works. Nevertheless I feel that I don't really understand Nix/NixOS and the foundations of my knowledge are very poor (thus I cannot create that package)

Additional context
I really want to learn NixOS. I feel that all the concepts behind it is what I expect from my desirable OS experience, nevertheless my experience has been that at the beginning I have to accept that I won't be able to use my desired environment (i3 + Gnome) because no one has created it before and I have to use Nix to understand Nix.

It's good that a lot of things are abstracted in documentation because no one wants to understand the internals of software in order to use it, but at the end there will be something that is very low level which hasn't been abstracted and in order to be able to perform that task you really need to understand the details and I feel that it is the missing piece in the Nix documentation.

At least that is my feeling, maybe (and probably) I have missed something

[Ericson2314]

Have you seen https://nixos.org/guides/nix-pills/ ?