Installing a program — what really happens

1. The promise

You'll understand that "install" is mostly just "copy these files into a known place and tell the OS about them." You'll be able to find any installed program on disk by hand, and you'll have VSCode installed for the rest of the course.

2. The mental model

Installing is a delivery driver dropping a recipe into your cookbook drawer and sticking a note on the fridge that says "we now have lasagne".

The cookbook drawer is /Applications on macOS or C:\Program Files\ on Windows. The sticky note is the registry entry (Windows) or the Launch Services database (macOS) — the index the OS uses to know what programs exist on this machine.

The vocabulary, said properly:

• An installer is a small program whose only job is to put the real program in the right place.
• A package manager is a tool that automates installing programs from the command line. You'll meet one in Ch 2.
• Preference files are the small data files programs write to remember your settings. They live in your home folder, usually hidden.

(DIAGRAM: what install actually does — Mermaid flowchart — downloaded file -> installer process -> copies program files to /Applications or Program Files -> writes registry or Launch Services entry -> menu item appears)

3. You do it, with me

We're going to install VSCode. This is the editor you'll use for the rest of the course.

Step 1. Download. Open your browser and go to https://code.visualstudio.com.

(SCREENSHOT: the VSCode download page at code.visualstudio.com — full window — the platform-correct download button highlighted)

Click the big download button. The site detects your OS and serves the right file: a .dmg for macOS, a .exe or .msi for Windows.

If you're on Apple Silicon (any Mac from 2020 onwards with an "M" chip), pick the Apple Silicon build. If you're on an older Intel Mac, pick the Intel build. If you're not sure, your "About This Mac" screen from unit 0.1 tells you.

Step 2. Find the downloaded file. Open Finder (macOS) or File Explorer (Windows) and go to your Downloads folder.

(SCREENSHOT: macOS Downloads folder showing VSCode.dmg — full window — file highlighted)

Step 3. Run the installer.

On macOS: double-click the .dmg. A window opens with the VSCode icon on the left and an Applications shortcut on the right. Drag the VSCode icon onto the Applications shortcut. That's it. Eject the disk image when it's done.

(SCREENSHOT: macOS installer drag-and-drop window for VSCode — full window — arrow visible)

On Windows: double-click the .exe. The installer opens. Read each screen before clicking Next.

(SCREENSHOT: Windows VSCode installer — license screen — full window — "I accept" radio button highlighted)

If Windows SmartScreen pops up saying "Windows protected your PC", click More info, then Run anyway. SmartScreen blocks anything it hasn't seen many other people run. The VSCode installer is safe — you downloaded it from the real site.

Step 4. Find VSCode on disk.

On macOS: open Finder, click Applications in the sidebar. Scroll to VSCode. It's there as Visual Studio Code.app.

(SCREENSHOT: macOS Finder showing /Applications with VSCode visible — full window)

On Windows: open File Explorer, paste C:\Program Files\Microsoft VS Code into the address bar, press Enter.

(SCREENSHOT: Windows File Explorer at C:\Program Files\Microsoft VS Code — full window)

That folder on disk is what the installer put there. The installer's other job — telling the OS the program exists — is why VSCode now shows up in Spotlight (macOS) or the Start menu (Windows).

Step 5 (peek only). Package managers do all of this from one command, no clicking. On macOS, Homebrew installs VSCode with brew install --cask visual-studio-code. On Windows, winget does it with winget install Microsoft.VisualStudioCode. You'll use these properly in Ch 2. Don't run them yet.

brew install --cask visual-studio-code

winget install Microsoft.VisualStudioCode

4. What you should be seeing

VSCode launches when you open it from Spotlight (macOS) or the Start menu (Windows). The first-launch welcome tab appears. You can close it. We come back to VSCode in Ch 2.

You can find the VSCode program file in /Applications (macOS) or C:\Program Files\Microsoft VS Code (Windows). It's a normal file you can browse to without the installer being involved again.

5. Common stumbles

• You ran VSCode straight from the mounted disk image (macOS). The disk image is a temporary mounted drive. The app vanishes next reboot. Fix: open Finder, drag VSCode from the disk image to /Applications, then eject the disk image.
• Wrong architecture downloaded. You downloaded the Intel build on an Apple Silicon Mac, or the ARM build on an Intel PC. The app runs but slower than it should. Fix: uninstall (move to Trash), re-download the correct build.
• Windows SmartScreen won't go away. The "More info -> Run anyway" path works for known-safe installers like VSCode.

• Dragging to Trash isn't a full uninstall. The program is gone, but preference files in your home folder stay behind. For most apps that's harmless. For full removal on macOS, use AppCleaner. On Windows, use Settings -> Apps -> Installed apps -> the app's three-dot menu -> Uninstall.

6. You should know