Module 01: Installation & setup

Last updated: Oct 19, 2026

Time: 15 minutes | Complexity: ⭐ Beginner

Goal

Get Claude Code installed and running on your system. Verify it works with your first command.

What you’ll learn

Install Claude Code for your platform (macOS / Linux / Windows)
Understand the basic prompt → response loop
Run your first command
Access the help system

Installation

macOS (recommended)

brew install anthropic/tap/claude-code

Verify:

claude --version

Linux

curl -sSL https://dl.claudecode.com/install.sh | bash

Verify:

claude --version

Windows

Download the installer from https://dl.claudecode.com/windows or use:

iex ((New-Object System.Net.WebClient).DownloadString('https://dl.claudecode.com/install.ps1'))

Docker (any platform)

docker run -it anthropic/claude-code:latest

First run

Navigate to any project directory and start Claude:

cd ~/my-project
claude

You’ll see:

Claude Code v2.x.x ready
Project: ~/my-project (git: main)
Context: 0% · Tokens available: 200,000

Type /help for commands or ask me anything
>

Essential commands

Command	Purpose
`/help`	Show all available commands
`/status`	Check context usage and session state
`/clear`	Start fresh (clears conversation history)
`Ctrl+C`	Cancel the current operation
`/exit`	Close Claude Code

Your first 5 minutes

Exercise 1: View available commands

/help

Review the command list. Notice:

Workflow: /plan, /rewind, /think
Navigation: /goto, /read
Memory: memory loading at startup
Advanced: /model, /mode

Exercise 2: Check session state

/status

You’ll see:

Context usage percentage
Available tokens
Current project
Git branch

Exercise 3: Ask Claude something

What files are in my project?

Claude will read the project structure and respond. This is the core loop:

Your prompt → Claude reads files → Claude suggests changes → You review → Apply

Exercise 4: Review a suggested change

If Claude suggests code changes, you’ll see:

A description of the change
A diff view (what’s being added/removed)
A prompt to accept or reject

Rule: Always review diffs before accepting. This protects you from unexpected changes.

The core concept: The loop

Every interaction follows this pattern:

┌─────────────┐
│ You ask     │
└──────┬──────┘
       │
       ▼
┌─────────────┐
│ Claude      │
│ reads files │
└──────┬──────┘
       │
       ▼
┌─────────────┐
│ Claude      │
│ suggests    │
│ changes     │
└──────┬──────┘
       │
       ▼
┌──────────────────┐
│ You review diff  │
│ and approve      │
└──────┬───────────┘
       │
       ▼
┌──────────────────┐
│ Changes applied  │
│ to your files    │
└──────────────────┘

Key concepts

Sessions

Each time you run claude, you start a new session. A session is a conversation with Claude that persists while you’re using Claude Code.

Sessions are not saved by default (they end when you exit)
Sessions are scoped to one project at a time
Your context grows as you ask more questions (max ~200K tokens)

Context

Context is how much of the conversation Claude remembers. It’s shown as a percentage (0-100%).

0-50%: Plenty of room, work freely
50-70%: Be selective, /compact optional
70%+: Run /compact to free space
90%+: You’ll be forced to clean up

Git awareness

Claude Code is git-aware. It:

Detects your current branch
Shows uncommitted changes
Helps with commits and reviews
Prevents accidental breaking changes

Validation: You’re ready if…

✓ You can run claude --version and see your installed version ✓ You can start Claude in a project with claude ✓ You understand the prompt → response loop ✓ You can see /status and understand what it shows ✓ You’ve reviewed at least one diff from Claude

What’s next?

Once you’re comfortable with this module, move to Module 02: Core Loop to understand:

How Claude reads your project
How context works in depth
How to structure requests for better results
Planning mode and thinking modes

Time to next module: Ready immediately (no prerequisites beyond running Claude once)

Troubleshooting

”claude: command not found”

Your installation didn’t complete. Try:

macOS: brew install anthropic/tap/claude-code again
Linux: Re-run the install script
Windows: Download the installer from https://dl.claudecode.com/windows

”Project not found”

Make sure you’re in a directory with a package.json, .git, or other project file. Claude Code works best in projects.

”Permission denied” (macOS)

Try:

chmod +x /usr/local/bin/claude

Resources

Official Docs: https://code.claude.com/docs
FAQ: See guide/ultimate-guide.md Appendix B
Examples: examples/ directory in this guide

Completed Module 01? → Ready for Module 02: Core Loop