tweaks

Author: mluukkai

src/content/3/en/part3b.md

@@ -110,8 +110,16 @@ If you decide to use [Fly.io](https://fly.io/) begin by installing their flyctl
 
 By default everyone gets two free virtual machines that can be used for running two apps at the same time.
 
-Note that the Fly.io instructions have only been added to this course on the 28th of August 2022. If you run into problems, please ask for help on Discord! If your build keeps failing due to unhealthy checks, try changing your port from 3001 to 8080.
-Don't forget to add your `cors` package to `dependencies` in `package.json` and you might need to remove the `morgan` code from the server application.
+Note that the Fly.io instructions have only been added to this course on the 28th of August 2022. If you run into problems, please ask for help on Discord! If your build keeps failing due to unhealthy checks, make sure that you have changed the bottom of the <i>index.js</i> file like so: 
+
+```js
+const PORT = process.env.PORT || 3001  // highlight-line
+app.listen(PORT, () => {
+  console.log(`Server running on port ${PORT}`)
+})
+```
+
+Don't forget to add your _cors_ package to _dependencies_ in _package.json_ and you might need to remove the _morgan_ code from the server application.
 
 Start by [authenticating](https://fly.io/docs/hands-on/sign-in/) via command line with the command