Nix / NixOS

Hello you all, so basically i installed Nix in my machine, and i wanted a way to install packages, with nix-env --install, and those packages share with the root account, i was reading about nix multi-user and i'm gonna be honest, i didn't understood shit, i need to enable daemon for both root and my user?, or this only works between users, not root?, etc. thanks for any answer!