You'll finish with: Claude Code running and pointed at your folder.
Claude Code is the version with everything switched on — the files, the agents, the hooks. It's built for programmers, but nothing stops you pointing it at a folder of business documents instead.
Check this before you start. Claude Code needs a Pro, Max, Team, Enterprise or Console account. The free Claude.ai plan doesn't include it. If you're on free, everything below will work right up until you sign in, and then stop.
There's a desktop app for Mac, Windows and Linux that gives you Claude Code without any of this. If the terminal isn't for you, download that instead and skip to the next chapter — you lose nothing from this course.
Still here? Good. The terminal version is worth the twenty minutes.
The Terminal is a window where you type commands instead of clicking. Mac: press Cmd+Space, type "terminal", hit enter. Windows: search for "PowerShell". It looks unfriendly. It's just a text box.
Four steps to a working setup
1. TerminalMac: Cmd+Space, type "terminal". Windows: search "PowerShell".2. InstallOne line — the right one for your machine. About a minute.3. Go to folderType cd then drag your folder onto the window.4. StartType claude and sign in.cd then drag the folder onto the Terminal window and press enter. That fills in the path for you.claude and press enter.# Mac, Linux, or WSL
curl -fsSL https://claude.ai/install.sh | bash
# Windows PowerShell (your prompt starts with PS C:\)
irm https://claude.ai/install.ps1 | iex
# Mac, if you already use Homebrew
brew install --cask claude-code
# Windows, if you already use winget
winget install Anthropic.ClaudeCodeUse the line for your own machine. The first one will not work in PowerShell and the second will not work on a Mac. On Windows, look at your prompt: PS C:\ means PowerShell. Plain C:\ means you're in CMD — open PowerShell instead, it's easier.
You have probably been told, correctly, never to paste a command off the internet that downloads a script and runs it. So here is what this one is, before you decide.
curl downloads a file. https://claude.ai/install.sh is Anthropic's own installer, on Anthropic's own domain — the same company you already pay. | bash runs it. It puts the Claude program in your user folder. It does not need your password and you should not be asked for one.
The reason this pattern is worth being suspicious of is that you're trusting whoever controls that web address. Here that's Anthropic, and you're already trusting them with your business documents. Check the address is claude.ai before you paste. If a guide anywhere ever gives you this pattern pointing at a domain you don't recognise, don't run it. That instinct is a good one — keep it.
If you'd rather not use it at all, Homebrew and winget above do the same job, and the desktop app avoids the terminal entirely.
About the npm install in older guides. npm install -g @anthropic-ai/claude-code still works and installs the same program, but it needs Node.js 22 or newer and it is no longer the recommended route. If you already installed that way there's nothing urgent to fix.
Type /init. Claude reads your folder and drafts a CLAUDE.md from what it finds. It won't know your voice or your clients — you add those — but it saves a blank page.
Type claude --version and press enter. It prints a version number like 2.1.211 (Claude Code). Then start it, and ask "what's in this folder?" — it should list your real files, by name.
If you get command not found, close the Terminal completely and open a new one first — the install needs a fresh window to be seen. If it still fails, run claude doctor, which checks the installation and tells you what's wrong. And if it installed fine but won't sign in, check your plan: Claude Code isn't included on the free tier.