diff --git a/README.md b/README.md
index 93618f7..1324be8 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,60 @@ This is a script to bundle/package tintd and hopefully publish it
 tintd is a [language protocol server](https://microsoft.github.io/language-server-protocol/)
 for [WGSL](https://gpuweb.github.io/gpuweb/wgsl/), the WebGPU Shading Language.
 
+# Updating
+
+This updates to the latest dawn and depot_tools
+
+```
+npm ci
+npm run update
+```
+
+# Building
+
+This builds for the local OS (win64,macOS-arm,linux)
+
+```
+npm ci
+npm run build
+```
+
+## Prerequisites
+
+### Windows
+
+Before running the build script above you must have
+Visual Studio C++ installed and have run the `vcvars64.bat` file.
+I've tested with Visual Studio Community Edition 2022
+
+Further you must have [cmake installed](https://cmake.org/download/)
+and either in your path or at it's standard place of `C:\Program Files\CMake`
+
+And you must have `node.js` installed, at least version 18. 
+I recommend using [nvm-windows](https://github.com/coreybutler/nvm-windows) to install it
+as it makes it easy to switch version
+
+### MacOS
+
+Before running the build script above you must have
+XCode installed and its command line tools
+
+Further you must have [cmake installed](https://cmake.org/download/)
+and either in your path or at it's standard place of `/Applications/CMake.app`
+
+And you must have `node.js` installed, at least version 18. 
+I recommend using [nvm](https://github.com/nvm-sh/nvm) to install it
+as it makes it easy to switch versions.
+
+### Linux (Ubuntu)
+
+Before running the build script above you need to install
+the following dependencies
+
+```
+sudo apt-get install cmake libxi-dev libxrandr-dev libxinerama-dev libxcursor-dev mesa-common-dev libx11-xcb-dev pkg-config
+```
+
+And you must have `node.js` installed, at least version 18. 
+I recommend using [nvm](https://github.com/nvm-sh/nvm) to install it
+as it makes it easy to switch versions.
diff --git a/build/update.js b/build/update.js
new file mode 100644
index 0000000..b6996a3
--- /dev/null
+++ b/build/update.js
@@ -0,0 +1,22 @@
+import path from 'path';
+import fs from 'fs';
+
+import {execute} from './execute.js';
+    
+const cwd = process.cwd(); 
+
+async function main() {
+  try {
+    process.chdir('third_party/dawn');
+    await execute('git', ['pull', 'origin', 'main']);
+    process.chdir(cwd);
+    process.chdir('third_party/depot_tools');
+    await execute('git', ['pull', 'origin', 'main']);
+   } catch (e) {
+    console.error(e);
+    console.error(e.stack);
+    process.exit(1);
+  }
+}
+
+main();
\ No newline at end of file
diff --git a/package.json b/package.json
index 54ebd89..abfc482 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,8 @@
   "main": "index.js",
   "type": "module",
   "scripts": {
-    "build": "node build/build.js"
+    "build": "node build/build.js",
+    "update": "node build/update.js"
   },
   "repository": {
     "type": "git",