How to Use Claude Code

Chapter 1: What Claude Code Actually Is

Claude Code is a command-line tool. That means it runs in your computer's terminal (the text-based window where programmers type commands). But here's the thing: you don't need to be a programmer. You talk to it in plain English.

Unlike chat-based AI where you copy and paste code back and forth, Claude Code can:

• Read and write files directly on your computer
• Run commands (install things, start programs, test code)
• Understand your whole project — it reads your files and knows how they connect
• Fix its own mistakes — when something breaks, it reads the error and fixes it
• Build complete projects from a single description

The mental model: Imagine a skilled programmer sitting at your computer. You tell them in plain English: "Build me a landing page with an email signup form that saves people's info to a database." And they just do it. That's Claude Code.

How it's different from other AI coding tools:

• GitHub Copilot suggests code as you type — you're still driving
• Cursor is an AI-powered code editor — you're still working in the editor
• Claude Code works in your terminal — it does everything by itself. You describe, it builds.

Who should use it:

• Non-technical founders: Build real apps without hiring a developer
• Programmers: Skip the boring parts. Focus on big-picture decisions.
• Creators and business owners: Build custom tools, scrapers, websites, and automations

Chapter 2: Getting It Set Up

Setting up Claude Code takes about 5 minutes.

Step 1: Install Node.js

Node.js is a program that Claude Code needs to run. Think of it like the engine that powers the tool.

1. Go to nodejs.org
2. Download the LTS (Long Term Support) version
3. Run the installer. Click "Next" through everything.

Step 2: Install Claude Code

Open your terminal:

• Mac: Open the app called "Terminal" (search for it in Spotlight)
• Windows: Open "Command Prompt" or "PowerShell" (search in Start menu)

Type this command and press Enter:

```

npm install -g @anthropic-ai/claude-code

```

Step 3: Log In

Type this and press Enter:

```

claude

```

It will ask you to log in to your Anthropic account. Follow the instructions on screen.

Step 4: You're Ready!

That's it. Claude Code is installed. You can now navigate to any folder on your computer and start building.

Chapter 3: Your First Project

Let's build something right now. We'll create a simple personal website.

Step 1: Create a Project Folder

In your terminal, type:

```

mkdir my-website

cd my-website

claude

```

This creates a new folder called "my-website," goes into it, and starts Claude Code.

Step 2: Tell Claude What to Build

Type something like:

"Build me a personal portfolio website. Include a home page with my name, an about section, a list of my projects, and a contact form. Make it look modern and clean. Use blue and white colors."

Step 3: Watch It Work

Claude Code will:

1. Plan what files it needs to create
2. Write all the code
3. Create all the files
4. If anything needs to be installed, it will ask your permission

Step 4: See Your Website

Claude will tell you how to view it. Usually something like:

```

Open index.html in your browser

```

Or it might start a local server for you.

That's It!

You just built a website by describing it in English. No coding knowledge needed.

Chapter 4: The Key Commands

Here are the most important things you can tell Claude Code:

Building New Things

• "Build me a [describe what you want]"
• "Create a new file called [name] that does [what]"
• "Add a [feature] to the existing project"

Fixing Things

• "There's an error. Fix it." (Claude reads the error and fixes it)
• "This page looks wrong on mobile. Fix the layout."
• "The contact form isn't sending emails. Debug it."

Understanding Your Project

• "Explain what this project does"
• "What files are in this project and what does each one do?"
• "Show me how the data flows through the app"

Improving Things

• "Make this page load faster"
• "Clean up this code and make it easier to read"
• "Add error handling so the app doesn't crash when something goes wrong"

Getting Help

• "What should I do next to improve this project?"
• "Is there a better way to do [something]?"

Chapter 5: Project Types

Claude Code can build almost anything. Here are the most common types:

Websites and Landing Pages

"Build me a landing page for my dog walking business. Include testimonials, pricing, and a contact form."

Web Applications

"Build a simple task management app where users can create, edit, and delete tasks. Include a login system."

Scripts (Small Helper Programs)

"Write a script that reads all the CSV files in this folder and combines them into one spreadsheet."

Automations

"Create an automation that checks my email every hour and sends me a text if any email contains the word 'urgent'."

APIs (Programs That Other Programs Talk To)

"Build an API that stores and retrieves customer information."

Chrome Extensions

"Build a Chrome extension that highlights all the prices on any webpage."

Chapter 6: Working With Existing Code

Claude Code isn't just for new projects. It can work with code that already exists.

Fixing Bugs

Navigate to your existing project folder, start Claude Code, and say:

"There's a bug where the login button doesn't work on mobile. Find and fix it."

Claude will read your project files, find the problem, and fix it.

Adding Features

"Add a dark mode toggle to this website."

"Add a search bar that filters the product list."

"Add an export-to-PDF button to this report page."

Improving Code

"This code works but it's messy. Clean it up and add comments explaining what each part does."

"This page loads slowly. Find what's causing the slowness and fix it."

Understanding Someone Else's Code

If you inherited a project and don't understand it:

"Explain this project to me like I'm a beginner. What does it do? How is it organized? What are the main files?"

Chapter 7: CLAUDE.md and Project Memory

CLAUDE.md is a special file you can put in your project folder. It teaches Claude about your project. Think of it like a cheat sheet you give to a new team member on their first day.

What to Put in CLAUDE.md

Create a file called CLAUDE.md in your project's main folder. Include:

```

What This Is

A website for my dog grooming business.

Important Info

• We use React (a web framework) for the frontend
• The database is Supabase
• Our brand colors are blue (#1a73e8) and white (#ffffff)
• Always use simple, friendly language in any text

Rules

• Never delete the customer database
• Always ask before making changes to the payment system
• Test everything on mobile before saying it's done

```

Why This Matters

Without CLAUDE.md, Claude Code starts every session fresh. With it, Claude immediately knows your project's context, rules, and preferences. It's like the difference between working with a stranger vs. a team member who knows the project.

Chapter 8: Advanced Workflows

Working on Big Projects

For bigger projects, break the work into phases:

1. "First, let's set up the project structure and install everything we need."
2. "Now build the homepage."
3. "Now build the user login system."
4. "Now connect everything to the database."

Take it step by step. Test after each phase.

Testing

Ask Claude to write tests (small programs that check if your main program works correctly):

"Write tests for the user login system. Test that signup works, login works, and wrong passwords are rejected."

Putting Your App Online (Deployment)

"Help me deploy this website to Vercel" (or Netlify, or Cloudflare Pages — these are free hosting services).

Claude will walk you through the steps to get your app live on the internet.

Chapter 9: Real Examples

Here are 5 things you can build with Claude Code right now:

Example 1: Personal Portfolio Website

"Build a personal portfolio website with sections for my bio, projects, skills, and a contact form. Make it responsive (works on phones and computers). Use a modern, minimal design."

Example 2: Simple Invoicing Tool

"Build a web app where I can create invoices, add line items, calculate totals, and export as PDF. Include a customer database."

Example 3: Email Newsletter Signup Page

"Build a landing page with a headline, description, and email signup form that saves emails to a Google Sheet."

Example 4: Social Media Post Scheduler

"Build a simple tool where I can write social media posts, pick a date and time, and have them saved to a database with a status of 'scheduled' or 'posted'."

Example 5: Customer Feedback Tracker

"Build a web app where customers can submit feedback through a form. I should see all feedback in a dashboard with filters by date and category."

Chapter 10: Fixing Problems

Problem: "Command Not Found"

This means Claude Code isn't installed correctly. Try reinstalling:

```

npm install -g @anthropic-ai/claude-code

```

Problem: Claude Seems Lost

If Claude doesn't understand your project, try:

1. Create a CLAUDE.md file explaining the project
2. Tell Claude to read the main files first: "Read the README and the main files, then tell me what this project does."

Problem: Something Broke

Don't panic. Tell Claude:

"Something broke. Here's what happened: [describe the problem]. The last thing I changed was [what you changed]. Fix it."

Claude will read the error, understand what went wrong, and fix it.

Problem: The Output Isn't What You Wanted

Be more specific in your description. Instead of "make it look better," say "change the header to use a larger font, add more white space between sections, and use the color blue (#1a73e8) for all buttons."

General Tips

• Always be specific about what you want
• Break big tasks into smaller steps
• Test frequently — don't build everything before checking if it works
• Use CLAUDE.md to give Claude context about your project
• Don't be afraid to start over on a section if it's not working

Your Claude Code Checklist

• [ ] Node.js installed
• [ ] Claude Code installed
• [ ] Logged in to your Anthropic account
• [ ] First project folder created
• [ ] First project built successfully
• [ ] Tried at least 2 project types
• [ ] Created a CLAUDE.md file for your project
• [ ] Successfully fixed a bug using Claude Code
• [ ] Put a project online (deployed it)

Claude Code is the closest thing to having a developer on call 24/7. You describe what you want in plain English. It builds it. The future of building software is just... talking about it.

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