diff --git a/README.md b/README.md
index 295bf17..1b6a6df 100644
--- a/README.md
+++ b/README.md
@@ -9,8 +9,9 @@ A basic Electron application needs just these files:
 - `package.json` - Points to the app's main file and lists its details and dependencies.
 - `main.js` - Starts the app and creates a browser window to render HTML. This is the app's **main process**.
 - `index.html` - A web page to render. This is the app's **renderer process**.
+- `preload.js` - A content script that runs before the renderer process loads.
 
-You can learn more about each of these components within the [Quick Start Guide](https://electronjs.org/docs/latest/tutorial/quick-start).
+You can learn more about each of these components in depth within the [Tutorial](https://electronjs.org/docs/latest/tutorial/tutorial-1-prerequisites).
 
 ## To Use
 
@@ -32,8 +33,7 @@ Note: If you're using Linux Bash for Windows, [see this guide](https://www.howto
 ## Resources for Learning Electron
 
 - [electronjs.org/docs](https://electronjs.org/docs) - all of Electron's documentation
-- [electron/electron-quick-start](https://github.com/electron/electron-quick-start) - a very basic starter Electron app
-- [hokein/electron-sample-apps](https://github.com/hokein/electron-sample-apps) - small demo apps for the various Electron APIs
+- [Electron Fiddle](https://electronjs.org/fiddle) - Electron Fiddle, an app to test small Electron experiments
 
 ## License
 
diff --git a/preload.js b/preload.js
index c2ff9c1..3610a37 100644
--- a/preload.js
+++ b/preload.js
@@ -1,5 +1,10 @@
-// All of the Node.js APIs are available in the preload process.
-// It has the same sandbox as a Chrome extension.
+/**
+ * The preload script runs before. It has access to web APIs
+ * as well as Electron's renderer process modules and some
+ * polyfilled Node.js functions.
+ * 
+ * https://www.electronjs.org/docs/latest/tutorial/sandbox
+ */
 window.addEventListener('DOMContentLoaded', () => {
   const replaceText = (selector, text) => {
     const element = document.getElementById(selector)
diff --git a/renderer.js b/renderer.js
index d3bdade..1e70849 100644
--- a/renderer.js
+++ b/renderer.js
@@ -1,6 +1,7 @@
-// This file is required by the index.html file and will
-// be executed in the renderer process for that window.
-// No Node.js APIs are available in this process because
-// `nodeIntegration` is turned off. Use `preload.js` to
-// selectively enable features needed in the rendering
-// process.
+/**
+ * This file is loaded via the <script> tag in the index.html file and will
+ * be executed in the renderer process for that window. No Node.js APIs are
+ * available in this process because `nodeIntegration` is turned off and
+ * `contextIsolation` is turned on. Use the contextBridge API in `preload.js`
+ * to expose Node.js functionality from the main process.
+ */