Ah great! .Yes, the NixOS manual and wiki are super helpful.
https://nixos.org/manual/nixos/stable/
https://nixos.wiki/wiki/Main_Page
Also, if you want a nice install and Gnome interface you can see my repo for install Sovran_SystemsOS_Light onto a laptop. This is the OS I use.
I will create an .iso soon.
https://git.sovransystems.com/Sovran_Systems/Sovran_SystemsOS_Light
Remember, NixOS uses two main files: the configuration.nix and the flake.nix all stored in /etc/nixos. The configuration.nix is where you put all the software you want to run on the computer and the flake.nix is the "repository" list on where the NixOS will download the software from.
If you keep that in mind, you should be off to a good start.