Updating INSTALL.md for WSL installs (#1265)

INSTALL.md

@@ -7,9 +7,11 @@ This document details the steps necessary to build a copy of Pokémon Platinum
 
 - [1. Setting Up Your Development Environment](#1-setting-up-your-development-environment)
   - [Windows Subsystem for Linux](#windows-subsystem-for-linux)
-    - [New Installs](#new-installs)
-    - [Existing Installs](#existing-installs)
-    - [Install Build Dependencies](#install-build-dependencies)
+    - [Windows WSL2](#windows-wsl2)
+        - [Developing in WSL2 from Windows](#developing-in-wsl2-from-windows)
+    - [Windows WSL1](#windows-wsl1)
+        - [Existing Installs](#existing-installs)
+        - [Install Build Dependencies](#install-build-dependencies)
   - [Windows with MSYS2](#windows-with-msys2)
   - [macOS](#macos)
   - [Linux](#linux)
@@ -26,13 +28,72 @@ This document details the steps necessary to build a copy of Pokémon Platinum
 
 ### Windows Subsystem for Linux
 
-> [!IMPORTANT]
-> If you intend to store your project on the Windows file system (or do not know
-> what that means), then use these instructions, which will guide you through
-> installing WSL version 1. If you intend to use WSL version 2, then instead
-> follow the instructions for [Linux](#linux).
+It's recommended to use [WSL2](#windows-wsl2) rather than WSL1 as your development environment. 
+If you still want to use WSL1, go [here](#windows-wsl1).
 
-#### New Installs
+#### Windows WSL2
+
+These instructions will enable you to build pokeplatinum using the more up-to-date WSL2 and
+develop on it with VSCode on Windows while it is stored in the Linux filesystem.
+
+1. In your start menu, search for `Windows PowerShell`. Open the Windows PowerShell app as administrator by right-clicking on it and selecting `Run as administrator`. 
+   Even if you're on an admin Windows profile, you always have to run it as admin.
+
+2. Install a new distro:
+    ```bash
+    wsl --install -d Ubuntu
+    ```
+    If this is your first time installing a WSL distro, then your computer will prompt
+    you to restart once finished. Do so, then open PowerShell as administrator again.
+
+    You can add `--name ` with a name on the end to the command to pick what name you'd like. 
+    By default it would be called `Ubuntu`.
+
+3. Check that `Ubuntu` (or whatever name you gave it) is installed in the list:
+    ```bash
+    wsl -l -v
+    ```
+    If the new distro you just made is not version 2, convert to version 2:
+    ```bash
+    wsl --set-version Ubuntu 2
+    ```
+
+4. Once the new distro is set up, enter it:
+    ```bash
+    wsl -d Ubuntu
+    ```
+
+5. Right now, you'll probably see your file system begin with `/mnt/c/`. That's the Windows file system.
+    Go to the Linux filesystem:
+    ```bash
+    cd ~
+    ```
+
+6. Install the pokeplatinum dependencies:
+    ```bash
+    sudo dpkg --add-architecture i386 && sudo apt update
+    sudo apt install bison flex g++ gcc-arm-none-eabi git make ninja-build pkg-config wget python3 xz-utils nasm libc6:i386 libpng-dev
+    ```
+
+7. Once that is done successfully, go to [Downloading the Repository](#2-downloading-the-repository) and continue from there.
+
+##### Developing in WSL2 from Windows
+
+With VSCode, you can modify files stored in Linux just like modifying files stored in Windows.
+
+1. Once you have cloned the pokeplatinum repo in your Linux filesystem and ensured that it is capable of building successfully, open VSCode in Windows (assuming you have downloaded it already). 
+
+   Go to extensions and find the WSL extension. Install it and make sure it's enabled.
+
+2. Back to your PowerShell terminal where you're running WSL2, run this command in the pokeplatinum directory to open it in VSCode on Windows:
+    ```bash
+    code .
+    ```
+    The first-time setup should automatically download the necessary extensions to develop against the Linux filesystem.
+
+3. You should now have pokeplatinum in Linux loaded in VSCode on Windows, standing by and ready for work!
+
+#### Windows WSL1
 
 Follow these instructions if you do not have an existing install of WSL.
 
@@ -73,7 +134,7 @@ finished, it will ask for a username and password as input.
 
 7. [`Install build dependencies`](#install-build-dependencies).
 
-#### Existing Installs
+##### Existing Installs
 
 Follow these instructions if you have an existing install of WSL, specifically
 `Ubuntu`.
@@ -111,7 +172,7 @@ install to a more recent version of `Ubuntu`:
 
 5. [`Install build dependencies`](#install-build-dependencies).
 
-#### Install Build Dependencies
+##### Install Build Dependencies
 
 1. Run the following to install build dependencies from the `Ubuntu` package
 registry:
@@ -263,6 +324,10 @@ To build the ROM, run:
 ```bash
 make
 ```
+or to skip the checksum if you want to modify the code:
+```
+make rom
+```
 
 If everything works, then the following ROM should be built: