Hey friend,
My recommendation is to keep things dead simple as you start out—no fancy channels or flake inputs and such, at least not where not necessary. I’ve found a lot of success in going slow, and not feeling rushed to do everything the NixOS way at first (for example, I still manage my dotfiles with GNU stow
instead of home-manager). I started off with a very simple flake and basically just using my configuration.nix to declare packages, gradually learning more from there. The Nix ecosystem is as extremely powerful as it is poorly documented—it unfortunately sometimes takes a while to (as you’ve noted) even just find information.
I’ve linked below two sites I found unbelievably helpful in my journey—the first one helps you get up and running with a very simple flake (and, yes, you will want to use a flake, even if it isn’t obvious right now why), and the second one is a huge search engine of all NixOS options, the first place I check when I’m putting something new on my system.
Good luck!
I find it infuriating to have to keep track of what’s system and what’s home-manager—why isn’t this all merged at this point?