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Guide · Claude Code

Claude Code for non-programmers: your first project

You don't need to read code to get real work out of Claude Code. This walkthrough takes you from install to a finished, useful tool built from your own data.

By Randy Torres · Updated · 8 min read

Claude Code ~/Documents/expense-report plan → build
Describe the result in plain English. Claude plans, you approve, it builds.
On this page
  1. What you need
  2. Step 1: Pick how you’ll use it
  3. Step 2: Make a project folder
  4. Step 3: Start a session in Plan mode
  5. Step 4: Describe the result, not the code
  6. Step 5: Approve the changes
  7. Step 6: Open it and check the numbers
  8. Step 7: Improve it in small steps
  9. Step 8: Save your progress and teach it the project
  10. Common mistakes to avoid
  11. What the Claude Code docs say
  12. Where to go from here
  13. Sources

Claude Code is Anthropic’s AI agent for building software. The name puts people off, because it sounds like a tool for engineers. In practice it’s the closest thing there is to having a developer sitting next to you: you describe what you want in plain English, it writes the files, runs them, checks its own work and asks before doing anything drastic.

The difference from a chat window is that Claude Code works on your computer, in a folder you choose. It can read the spreadsheets in that folder, create new files, and run the programs it writes. So instead of copying code out of a chat and wondering where to paste it, you end up with a finished thing you can open.

This guide builds one small project from start to finish: a one-page expense report that reads a spreadsheet of transactions and shows totals by category with a chart. It’s a good first project because you can check whether the answer is right just by looking at it.

What you need

  • A paid Claude plan. Claude Code needs Pro, Max, Ultra, Team or Enterprise. Pro is enough for this project. Every plan has usage limits, and long sessions can hit them.
  • A Mac, Windows or Linux computer.
  • A CSV of transactions. Export one from your bank or card account, or from your accounting tool. Any file with a date, a description and an amount works. If you’d rather not use real data, ask Claude to invent a sample file in step 3.

Step 1: Pick how you’ll use it

There are two ways in, and both use the same Claude Code underneath.

The desktop app (easiest). Download the Claude app from claude.com/download, sign in, and click the Code tab at the top. Nothing else to install. This guide uses the desktop app.

The terminal. If you’re comfortable typing commands, the official installer is one line. On Mac or Linux, open Terminal and run:

curl -fsSL https://claude.ai/install.sh | bash

On Windows, open PowerShell and run:

irm https://claude.ai/install.ps1 | iex

Then type claude inside a folder to start, and log in when it asks. Anthropic’s docs include a short terminal guide for first-timers if you want to go this way.

Step 2: Make a project folder

Create a new, empty folder somewhere easy to find, such as Documents/expense-report. Copy your CSV into it and give it a simple name like transactions.csv.

Keep it to a folder that holds only this project. Claude Code can read and change what’s inside the folder you give it, so don’t point it at your whole Documents folder or anything with files you care about.

Step 3: Start a session in Plan mode

In the desktop app’s Code tab:

  1. Choose Local as the environment. That means Claude works with the files on your machine.
  2. Click Select folder and choose your expense-report folder.
  3. Open the permission mode selector next to the send button and choose Plan.

Permission modes control how much Claude does without asking. Plan means it only reads and proposes, without changing any files. Manual means it asks before each edit or command. Accept edits lets it change files without asking. Auto lets a safety check approve routine actions for you. For a first project, start in Plan and switch to Manual when you’re ready to build, so you see every change before it happens. (In the terminal version, press Shift+Tab to cycle through the modes.)

Step 4: Describe the result, not the code

Type something like this:

“In this folder there’s a file called transactions.csv with my card transactions. I want a single web page I can open in my browser that shows: total spending for the month, spending by category as a bar chart, and my ten biggest purchases. Categorize each transaction from its description (groceries, dining, travel, software, other). I don’t write code, so keep everything in as few files as possible and tell me how to open the result.”

Notice what the prompt includes: where the data is, what you want to see, and who you are. You didn’t mention a programming language or library, and you don’t need to.

Claude reads the CSV and comes back with a plan. Read it the way you’d read a contractor’s quote. Does it understand your columns? Are the categories right for your spending? If something’s off, say so in plain words: “Put Uber and Lyft under travel, not other.” Once the plan looks right, switch the mode to Manual and tell it to go ahead.

Step 5: Approve the changes

In Manual mode, Claude shows each file it wants to create and waits. You’ll see a diff view: new lines in green, removed lines in red. You don’t have to understand every line. Check the bits you can read, like file names, category names and labels, and click Accept.

It may also ask to run a command, often to check that the numbers add up. If it explains what the command does and it stays inside your folder, approve it. If you’re unsure, ask: “What does that command do, in one sentence?”

Step 6: Open it and check the numbers

When Claude says it’s done, ask it to open the page, or double-click the HTML file in your folder. You should see your total, a bar chart and a top-ten list.

Now do the most important step: check one number by hand. Open the CSV in Excel or Google Sheets, add up one category yourself, and compare. If it doesn’t match, tell Claude exactly what you found:

“The dining total shows $412 but when I add it up in Excel I get $389. Find out why.”

This is where Claude Code shines compared to a chat window. It can open the data, find that it counted a refund as spending, fix it and re-check, all without you touching the code.

Step 7: Improve it in small steps

Once the basics are right, add one thing at a time:

  • “Add a dropdown to switch between months.”
  • “Flag any subscription that charged me more this month than last month.”
  • “Make it look cleaner: white background, one accent color, bigger numbers.”
  • “Add a button so I can load next month’s CSV without changing any files.”

Small requests are easier to check than big ones. If a change goes wrong, say “undo that last change” and it will.

Step 8: Save your progress and teach it the project

Two habits make the next session easier.

Keep a history. Ask: “Set up version history for this folder with Git and save a snapshot called ‘first working version’.” Git is the tool developers use to save checkpoints. Now you can always say “go back to the first working version”.

Write down the context. Type /init. Claude Code writes a file called CLAUDE.md that describes the project. Every future session in this folder reads it first, so you don’t have to explain it all again. You can add your own notes to it, like “categories: groceries, dining, travel, software, other” or “always explain changes in plain English”.

To leave, type /exit or close the session. Next time, open the same folder and it picks up from the CLAUDE.md.

Common mistakes to avoid

  • Asking for everything at once. “Build me a full finance app” produces something big you can’t check. Build one screen, check it, then add.
  • Skipping the check. AI-written tools can be confidently wrong. Always test one result against a number you know.
  • Using sensitive data on day one. Practise with a sample or a low-stakes export. Read your company’s AI policy before using work data.
  • Approving what you don’t understand. Asking “why?” costs nothing. A good session is a conversation, not a series of clicks on Accept.

What the Claude Code docs say

Setup facts from Anthropic’s documentation, current as of November 2026.

Where to go from here

The same method works for anything you do repeatedly with files: a script that renames and sorts a folder of invoices, a tool that turns meeting notes into a formatted summary, a tracker that merges three spreadsheets every Monday. Describe the result, plan first, build in small steps, check a number.

For inbox tasks, see how to automate Gmail with Claude. For spreadsheets you’d rather keep in Excel, Using AI with Excel covers cleaning, formulas and reports without leaving the workbook.

In our two-day class, the build lab on Day 2 is exactly this: everyone builds the same multi-step automation from a written specification with an AI coding assistant, then tests and fixes it.

Sources

Applied AI Workflow Automation · Boston

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