flesh out the oneclick tutorial a bit

en/nixos-install-oneclick.md

@@ -4,17 +4,46 @@ order: 3
 
 # Install NixOS directly from a remote flake
 
->[!WARNING] To Write
-> This tutorial has not been written yet. What you see below are just rough notes.
+>[!WARNING] WIP
+> This tutorial has not been completed yet.
 
-Boot from a NixOS install live CD ("minimal" version is sufficient), and then:
+Unlike the previous tutorials ([[nixos-install-flake|1]]; [[nixos-install-disko|2]]), the goal here is to near-fully automate our NixOS install using one command (see the next section)
+
+{#install}
+## How to install
+
+Boot your computer from any NixOS install live CD ("minimal" version is sufficient), and then from the terminal run:
 
 ```sh
-# Assuming your system is x86_64-linux
+# Assuming 
+# - your system is x86_64-linux
+# - your harddrive device is /dev/sda
 sudo nix \
     --extra-experimental-features 'flakes nix-command' \
     run github:nix-community/disko#disko-install -- \
     --flake "github:nixos-asia/website?dir=global/nixos-install-oneclick#oneclick" \
     --write-efi-boot-entries \
     --disk main /dev/sda
 ```
+
+Here, `"github:nixos-asia/website?dir=global/nixos-install-oneclick#oneclick"` is [our own sample configuration](https://github.com/nixos-asia/website/tree/master/global/nixos-install-oneclick) flake. Feel free to substitute it with your own flake. 
+
+If everything goes well, you should see the installation successfully finish with a message like this below:
+
+```text
+...
+Random seed file /boot/loader/random-seed successfully written (32 bytes).
+Successfully initialized system token in EFI variable with 32 bytes.
+Created EFI boot entry "Linux Boot Manager".
+installation finished!
+```
+
+- Take note of the IP address of your machine using `ifconfig`.
+- Reboot your computer (or VM)! And you should boot into NixOS. 
+- Test ssh access using `ssh root@<ip-addr>`
+
+## User management
+
+The above flake is meant to be used on a server. As such, it authorizes root access through SSH keys. 
+
+- [ ] If you are setting up a desktop, you may have to ...