Update to 4 in STEP and README.md

Author: github-actions[bot]

.github/steps/-step.txt

@@ -1 +1 @@
-3
+4

README.md

@@ -16,77 +16,84 @@ _Develop code using GitHub Codespaces and Visual Studio Code!_
 </header>
 
 <!--
-  <<< Author notes: Step 3 >>>
+  <<< Author notes: Step 4 >>>
   Start this step by acknowledging the previous step.
   Define terms and link to docs.github.com.
 -->
 
-## Step 3: Customize your codespace!
+## Step 4: Personalize your codespace!
 
-_Nice work! :tada: You created a codespace with a custom image!_
+_Nicely done customizing your codespace!_ :partying_face:
 
-You can customize your codespace by adding VS code extensions, adding features, setting host requirements, and much more.
+When using any development environment, customizing the settings and tools to your preferences and workflows is an important step. GitHub Codespaces offers two main ways of personalizing your codespace: `Settings Sync` with VS Code and `dotfiles`.
 
-Let's customize some settings in the `devcontainer.json` file!
+`Dotfiles` will be the focus of this activity.
 
-### :keyboard: Activity: Add customizations to the `devcontainer` file
+**What are `dotfiles`?** Dotfiles are files and folders on Unix-like systems starting with . that control the configuration of applications and shells on your system. You can store and manage your dotfiles in a repository on GitHub.
 
-1. Navigate to the `.devcontainer/devcontainer.json` file.
-1. Add the following customizations to the body of the file before the last `}`.
+Let's see how this works!
 
-   ```jsonc
-    ,
-    // Add the IDs of extensions you want installed when the container is created.
-    "customizations": {
-        "vscode": {
-            "extensions": [
-                "GitHub.copilot"
-            ]
-        },
-        "codespaces": {
-            "openFiles": [
-                "codespace.md"
-            ]
-        }
-    }
-   ```
+### :keyboard: Activity: Enable a `dotfile` for your codespace
+
+1. Start from the landing page of your repository.
+1. In the upper-right corner of any page, click your profile photo, and then click **Settings**.
+1. In the **Code, planning, and automation** section of the sidebar, click **Codespaces**.
+1. Under **Dotfiles**, select **Automatically install dotfiles** so that GitHub Codespaces automatically installs your dotfiles into every new codespace you create.
+1. Click **Select repository** and then choose your current skills working repository as the repository from which to install dotfiles.
 
-1. Click **Commit changes** and then select **Commit changes directly to the `main` branch**.
-1. Create a new codespace by navigating to the landing page of your repository.
+### :keyboard: Activity: Add a `dotfile` to your repository and run your codespace
+
+1. Start from the landing page of your repository.
 1. Click the **Code** button located in the middle of the page.
 1. Click the **Codespaces** tab on the box that pops up.
 1. Click the **Create codespace on main** button.
 
    > Wait about **2 minutes** for the codespace to spin itself up.
 
-1. Verify your codespace is running, as you did previously.
-1. The `codespace.md` file should show up in the VS Code editor.
-1. The `copilot` extension should show up in the VS Code extension list.
+1. Verify your codespace is running. The browser should contain a VS Code web-based editor and a terminal should be present such as the below:
 
-   This will add a VS Code extension as well as open a file on start up of the codespace.
+   ![codespace1](https://user-images.githubusercontent.com/26442605/207355196-71aab43f-35a9-495b-bcfe-bf3773c2f1b3.png)
 
-Next lets add some code to run upon creation of the codespace!
+1. From inside the codespace in the VS Code explorer window, create a new file `setup.sh`.
+1. Add the following code inside of the file:
 
-### :keyboard: Activity: Execute code upon creation of the codespace
+   ```bash
+   #!/bin/bash
 
-1. Edit the `.devcontainer/devcontainer.json` file.
-1. Add the following postCreateCommand to the body of the file before the last `}`.
+   sudo apt-get update
+   sudo apt-get install sl
+   ```
+
+1. Save the file.
+   > **Note**: The file should autosave.
+1. Commit the file changes. From the VS Code terminal enter:
 
-   ```jsonc
-    ,
-    "postCreateCommand": "echo '# Writing code upon codespace creation!'  >> codespace.md"
+   ```shell
+   git add setup.sh --chmod=+x
+   git commit -m "Adding setup.sh from the codespace!"
    ```
 
-1. Click **Commit changes** and then select **Commit changes directly to the `main` branch**.
-1. Create a new codespace by navigating to the landing page of your repository.
-1. Click the **Code** button located in the middle of the page.
-1. Click the **Codespaces** tab on the box that pops up.
+1. Push the changes back to your repository. From the VS Code terminal, enter:
+
+   ```shell
+   git push
+   ```
+
+1. Switch back to the homepage of your repository and view the `setup.sh` to verify the new code was pushed to your repository.
+1. Close the codespace web browser tab.
 1. Click the **Create codespace on main** button.
 
    > Wait about **2 minutes** for the codespace to spin itself up.
 
 1. Verify your codespace is running, as you did previously.
-1. Verify the `codespace.md` file now has the text `Writing code upon codespace creation!`.
+1. Verify the `setup.sh` file is present in your VS Code editor.
+1. From the VS Code terminal, type or paste:
+
+   ```shell
+   /usr/games/sl
+   ```
+
+1. Enjoy the show!
 1. Wait about 20 seconds then refresh this page (the one you're following instructions from). [GitHub Actions](https://docs.github.com/en/actions) will automatically update to the next step.
 
 <footer>