Add instructions to enable WSL 2 (#458)

* Add instructions to enable WSL 2

* Update README.md

* Update README.md

---------

Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

README.md

@@ -11,15 +11,21 @@ Modules for running NixOS on the Windows Subsystem for Linux
 
 ## Quick Start
 
-1. Download `nixos-wsl.tar.gz` from [the latest release](https://github.com/nix-community/NixOS-WSL/releases/latest).
+1. Enable WSL if you haven't done already:
 
-2. Import the tarball into WSL:
+  - ```powershell
+    wsl --install --no-distribution
+    ```
+
+2. Download `nixos-wsl.tar.gz` from [the latest release](https://github.com/nix-community/NixOS-WSL/releases/latest).
+
+3. Import the tarball into WSL:
 
 - ```powershell
   wsl --import NixOS $env:USERPROFILE\NixOS\ nixos-wsl.tar.gz
   ```
 
-3. You can now run NixOS:
+4. You can now run NixOS:
 
 - ```powershell
   wsl -d NixOS