Install Claude Code and take your first look around

Claude Code is the tool that does the building. Everything after this lesson is you and it, in a terminal, talking. This lesson gets it installed, gets you logged in, and shows you the handful of things on the screen you actually need to understand.

Step 1: Install it

Open a terminal (Lesson 2, Step 1) and run the command for your system.

Mac:

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

Windows (PowerShell):

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

The installer prints a few lines and finishes in under a minute. Close the terminal and open a new one, then prove it:

claude --version

You should see a version number followed by (Claude Code).

Windows and Git. In Lesson 2 you installed Git for Windows. That is not only for saving your work; Claude Code uses it to get a proper command shell. Without it Claude Code still runs, but some commands behave differently. If you skipped Git, go back and install it now.

Step 2: Log in

Go to your projects folder and start Claude Code:

cd ~/projects
claude

The first time, it asks a couple of setup questions before the login: pick a color theme (any is fine), and whether you trust the files in this folder (say yes; it asks this once for every new folder, so you will see it again in Lessons 4 and 6). Then it asks you to log in. Choose the option for a Claude subscription (Pro, Max or Team). Your browser opens. Sign in with the same account you use at claude.ai, approve the connection, and come back to the terminal. It says you are logged in and drops you at a prompt.

You only do this once. If you ever need to switch accounts, type /login inside Claude Code.

Step 3: Learn the screen

You are now looking at the Claude Code prompt. There are five things worth knowing.

The input box at the bottom is where you type. Press Enter to send. That is a conversation, not a search box: write full sentences, ask follow-up questions, say “no, I meant…” when it misunderstood.

The folder you are in is shown above the prompt. Claude Code works on files in that folder and its subfolders; anything outside it, it asks you first. This is why we always start it from inside a project folder. Right now you are in ~/projects, which is empty, and that is fine for a look around.

Slash commands start with /. Type / on its own and a menu appears. The ones you will use:

Command	What it does
/help	Lists the commands.
/clear	Wipes the conversation and starts fresh. Use it between unrelated tasks; a long conversation makes Claude slower and more forgetful.
/init	Writes a notes file about the project so Claude remembers how things work. You will use it in Lesson 6.
/exit	Quits. (Pressing Ctrl + C twice also works.)

Permission mode is shown near the bottom of the screen. It controls how much Claude does without asking you. Press Shift + Tab to cycle through the modes. The status bar tells you which one you are in:

Status bar says	What it means
manual mode on	Claude asks before it edits a file or runs a command that matters. You say yes or no to each. This is where you want to be for this course.
accept edits on	Claude edits files without asking, but still asks before commands. Skip past this one.
plan mode on	Claude reads and thinks and proposes a plan, but changes nothing until you approve. Start any task bigger than a one-line change here.
auto mode on	A classifier approves most actions for you. Convenient later, not yet.

One thing to know: your very first session after installing starts in manual mode. Every session after that, on a Pro, Max or Team plan, starts in auto mode. So from Lesson 4 onward, the first thing you do in every new session is press Shift + Tab until the bar says manual mode on. It becomes a reflex. Once you have the commit habit from Lesson 5, you can decide to leave it in auto; not before.

The approval question. When Claude wants to edit a file or run a command, it shows you what and asks. Read it. Not the code; the description. “Create the file app/page.tsx with a client list” is fine. “Delete the database folder” is not. You can say no, and you can type a reason, and it will change course.

Step 4: Say hello

Type this and press Enter:

What can you do, and what can you not do? Answer in plain English for someone who has never written code.

Read the answer. Then try:

What folder are you in right now, and what is in it?

It will tell you it is in your projects folder and that it is empty. It may run a command to look; if it asks permission, say yes. This is the pattern for the whole course: you ask, it does, you look at what it did.

Now quit:

/exit

Check your work

• claude --version prints a version.
• Starting claude inside ~/projects drops you at a prompt without asking you to log in again.
• You know how to press Shift + Tab and can read which mode you are in from the status bar.
• You have asked it at least two questions and read the answers.
• You know /exit gets you out.

If something went wrong

The install command fails with a 403, a curl error, or a syntax error mentioning <. On Windows, check the prompt: if it does not start with PS, you are in the old Command Prompt, not PowerShell. Open PowerShell and try again. On either system, if the error persists, the Claude Code docs have a troubleshooting page that matches the exact error to a fix. Search for “Claude Code troubleshoot installation.”

claude says the command is not found after installing. Fresh terminal window. Every time.

The browser opened but the terminal is still waiting. Look at the browser. There is usually an approve button you have not clicked, or it is asking you to sign in first. If you closed the browser tab, press Ctrl + C in the terminal and run claude again.

It says my subscription does not include Claude Code. Claude Code needs Pro, Max or Team. The free plan does not include it. Upgrade at claude.ai, then run /login again.

It is asking me to approve every tiny thing. That is manual mode doing its job. It gets less annoying, and in Lesson 5 you will learn the habit that makes it safe to loosen. Do not loosen it yet.

Next

Lesson 4 is the most important one in the course: how to talk to this thing so you get what you meant, not what you said.