Setting Up VS Code with an AI Coding Assistant

MKT 566 · Decision Making Using Marketing Analytics · Fall 2026

This guide assumes you have never installed a programming tool before. Follow it top to bottom and you will end up with everything you need for this course: VS Code (the program where we will write and run code) and one AI coding assistant working inside it.

Two things before you start:

Step 1: Install VS Code

VS Code (Visual Studio Code) is a free program from Microsoft. It is a text editor for code: think of it as Word, but for programs and data analysis. All three AI assistants run inside it.

On a Mac

  1. Go to https://code.visualstudio.com/download and click the blue Mac button. A file like VSCode-darwin-universal.zip lands in your Downloads folder.
  2. Open your Downloads folder and double-click the zip file. It unpacks into an app called Visual Studio Code.
  3. Drag Visual Studio Code into your Applications folder (open a Finder window, Applications is in the left sidebar).
  4. Open your Applications folder and double-click Visual Studio Code. If macOS asks whether you are sure you want to open an app downloaded from the internet, click Open.

On Windows

  1. Go to https://code.visualstudio.com/download and click the blue Windows button. An installer like VSCodeUserSetup-x64.exe lands in your Downloads folder.
  2. Double-click the installer and click through it: accept the agreement, then keep clicking Next (the default choices are all fine), then Install, then Finish.
  3. VS Code opens automatically. Later you can start it from the Start menu.

First launch

The first time VS Code opens you will see a Welcome tab, and possibly popups asking about themes or settings. You can close all of that. The two parts of the window you need to know:

  • The left sidebar has a column of icons. The one made of four squares is Extensions: the app store for VS Code add-ons. That is where you install your AI assistant.
  • The bottom bar (the thin strip at the very bottom) is called the Status Bar. Copilot lives there.

Step 2: Pick ONE AI assistant and set it up

All three assistants do the same job for this course: you type a request in plain English (“read this CSV file and plot sales by month”) and they write, explain, and fix code with you. Pick based on what you already pay for:

Account you need Cost
Claude Code A Claude account Requires a paid Claude plan (Pro, about $20/month, or higher). If you already pay for Claude, use this.
Codex A ChatGPT account Included with paid ChatGPT plans (Plus, about $20/month, and up). If you already pay for ChatGPT, use this.
GitHub Copilot A free GitHub account Has a free plan, and verified students get the paid tier free through GitHub Education. If you do not want to pay anything, use this.

They are all good. If you have no subscriptions and no preference, GitHub Copilot with the free student upgrade is the budget option.

Option A: Claude Code

You need a Claude account with a paid plan (Pro or higher). If you do not have one, sign up at https://claude.ai first.

  1. In VS Code, press Cmd+Shift+X (Mac) or Ctrl+Shift+X (Windows). This opens the Extensions panel.
  2. In the search box at the top, type Claude Code.
  3. Click the result named Claude Code, published by Anthropic, then click the blue Install button.
  4. A spark-shaped icon appears in the left sidebar. Click it: the Claude Code panel opens.
  5. Click Sign in. Your web browser opens; log in with your Claude account and click Authorize. Then return to VS Code.
  6. A short Learn Claude Code checklist appears the first time; it is a good two-minute tour, or dismiss it with the X.

If the icon does not appear after installing, quit and reopen VS Code.

Full official instructions: https://code.claude.com/docs/en/vs-code

Option B: Codex

You need a ChatGPT account on a paid plan (Plus or higher). If you do not have one, sign up at https://chatgpt.com first.

  1. In VS Code, press Cmd+Shift+X (Mac) or Ctrl+Shift+X (Windows) to open the Extensions panel.
  2. In the search box, type Codex.
  3. Click the result named Codex – OpenAI’s coding agent, published by OpenAI, then click Install.
  4. A Codex icon appears in the left sidebar. Click it and choose Sign in with ChatGPT; your browser opens to log in, then return to VS Code.

Full official instructions: https://developers.openai.com/codex/ide

Option C: GitHub Copilot

Copilot is built into VS Code; there is nothing extra to install. You just need a GitHub account (GitHub is a website where programmers store code; our course materials live there too).

  1. If you do not have a GitHub account: go to https://github.com and click Sign up (it is free; use any email).
  2. In VS Code, look at the Status Bar at the very bottom of the window and click the Copilot icon (or the chat icon at the top of the window), then choose Use AI Features / Set up Copilot.
  3. Click Sign in, and log in with your GitHub account in the browser when it opens.
  4. That is it: without a subscription you automatically get Copilot Free (a monthly allowance of code completions and chat).

Free upgrade for students: verified students get Copilot’s paid tier for free. Go to https://github.com/education, click Join GitHub Education, and verify with your USC email address and proof of enrollment. Approval usually takes a few days, and Copilot then unlocks automatically on your account.

Full official instructions: https://code.visualstudio.com/docs/copilot/setup

Step 3: Set up R

VS Code and your AI assistant are ready, but they still need R itself: the program that actually runs our analysis code. That is a separate 15-minute setup with its own companion guide: Running R Code in VS Code. Follow it now (it picks up exactly where this guide leaves off), then come back here for the final test.

Step 4: Test that everything works

  1. In VS Code, choose File → Open Folder… and open any folder (for example, create an empty folder called mkt566 in your Documents first, and after Thursday’s class use the course code folder you downloaded).
  2. Open your assistant’s chat: click the spark icon (Claude Code), the Codex icon, or the chat icon at the top (Copilot).
  3. Type: “Create a file called hello.R that prints Hello MKT566, run it, and explain what it does.”

If the assistant creates the file, runs it, and you see Hello MKT566 in the output, you are done. Welcome to coding in 2026.

If something goes wrong

  • The extension installed but its icon does not show up. Quit VS Code completely and reopen it. (Or press Cmd+Shift+P / Ctrl+Shift+P, type “Reload Window”, and press Enter.)
  • The sign-in browser page never appears, or sign-in seems stuck. Reload the window (previous bullet) and click Sign in again.
  • Claude Code / Codex asks you to subscribe. Those two require a paid Claude / ChatGPT plan. If you do not want one, use GitHub Copilot (Option C) instead.
  • Anything else. Ask the assistant that IS working (even the chatbot on claude.ai or chatgpt.com): paste the error message and ask what to do. This is a genuinely useful habit for the whole course.
  • Still stuck? Bring your laptop to office hours: Davide (Tue 2 to 4 pm, HOH 332) or Raghav, our TA (Thu 2:30 to 4:30 pm, HOH 311). We will get you running in a few minutes.