Welcome to Claude Code Basics for Data Visualization! In this course, you'll learn how to use Claude Code, an AI-powered assistant that helps you write code, analyze data, and create visualizations. Think of Claude Code as a knowledgeable coding partner with whom you can chat directly from your terminal.

Before we dive into creating charts and analyzing datasets, we need to get comfortable with the basics. In this lesson, you'll learn how to open Claude Code, have a simple conversation with it, start fresh conversations when needed, close it when you're done, and come back to your work later. These might seem like small steps, but they're essential for everything else you'll do in this course. By the end of this lesson, you'll feel confident navigating in and out of Claude Code without any stress.

Creating data visualizations used to require a steep learning curve. You needed to master programming languages, memorize chart library syntax, troubleshoot formatting issues, and spend hours reading documentation just to produce a single graph. Many people with valuable data insights never shared them because the technical barriers were too high.

Today, AI-powered coding assistants like Claude Code are changing everything. These tools don't just autocomplete your code—they understand context, reason through problems, and collaborate with you in real-time conversations. Behind the scenes, Claude Code can use various tools to help you: searching through documentation, exploring your data files, writing visualization code, running that code to generate charts, and even viewing the resulting images to review them with you. You don't need to understand exactly how all of this works right now—we'll explore these capabilities in detail throughout the course.

This shift matters because it puts data visualization within reach for everyone. Tasks that once required years of programming experience—like creating interactive dashboards or styling publication-ready charts—can now be accomplished by anyone willing to clearly describe what they want to see. You don't need to memorize matplotlib parameters or remember pandas function names. You need to understand your data, know what story you want to tell, and guide Claude Code toward visualizations that communicate your insights effectively. The most valuable skill is no longer coding expertise—it's clear thinking about your data and effective communication of what you want to show.

Imagine you have a dataset of sales figures from the past year, and your manager asks you to find trends and present your findings at the next team meeting. Without Claude Code, you might spend hours writing Python scripts, troubleshooting chart formatting, and second-guessing your analysis. With Claude Code, the workflow transforms completely.

You start by telling Claude Code about your dataset and what questions you want to answer. Claude helps you load the data, identifies potential issues like missing values or outliers, and suggests which patterns might be worth exploring. When you decide you want to see monthly trends, Claude writes the visualization code for you. You review the chart, and if the colors don't work or the labels are hard to read, you simply describe what you'd like changed. Claude iterates with you until the visualization communicates exactly what you need.

When it's time to prepare your presentation, Claude can help you summarize the key insights, suggest how to frame your findings for a non-technical audience, and even recommend which charts to include and which to leave out. Throughout this entire process, you remain in control—deciding what questions matter, choosing which visualizations tell the right story, and determining how to present your conclusions.

Think of it this way: you become the pilot, setting the destination and making the key decisions. Claude Code becomes your co-pilot, handling the technical navigation, monitoring the instruments, and executing the maneuvers you command. The vision is yours; the execution becomes a collaboration.

During this course, you'll be using the CodeSignal's IDE and coding environment, which comes with Claude Code already installed and ready to use. This means you can jump straight into learning without worrying about downloads, configurations, or compatibility issues. Everything has been set up for you, so you can focus entirely on learning how to use Claude Code for data visualization.

Additionally, Claude Code is already authenticated in your learning environment. You don't need to set up your own Anthropic account or configure a payment method. All the technical setup has been handled for you, allowing you to start practicing immediately without any barriers.

If you're interested in using Claude Code on your own computer after completing this course, you can follow the installation steps at https://claude.com/product/claude-code. The installation process is straightforward, and you'll need to create an Anthropic account and set up billing. But for now, you don't need to think about any of that. Your learning environment is ready, and you can start practicing right away.

To start Claude Code, open your terminal and type claude, then press Enter. You'll see Claude Code launch with a welcome screen:

Since you're working in CodeSignal's IDE, Claude Code launches immediately. If you were running this on your own computer for the first time, you would need to authenticate through your browser before the welcome screen appears. But here, that's already handled for you.

The welcome screen shows the logo on the left, along with the AI model version (Sonnet 4.5) and your current directory. On the right, you'll see helpful tips and your recent activity. Below the welcome screen is the prompt (>), where you'll type your messages to Claude Code.

Now that Claude Code is running, let's have a simple conversation with it. At the prompt, type Hi and press Enter. You'll see Claude Code respond to your greeting:

Notice how Claude Code responds with a bullet point (●) before its message. This helps you distinguish between what you type and what Claude Code says back to you. The response is friendly and offers to help with your work.

Let's ask Claude Code to introduce itself. Type Who are you? at the next prompt and press Enter:

Claude Code gives you a detailed explanation of what it can do. You'll see it mentions tasks like writing code, debugging, working with files, and explaining concepts. Don't worry about understanding all of these capabilities right now. In future lessons, you'll learn how to use Claude Code specifically for data visualization tasks. For now, just know that you can have a conversation with it by typing messages and pressing Enter.

Sometimes you'll want to start a completely new conversation with Claude Code without continuing your current one. Maybe you've finished one task and want to begin something entirely different, or perhaps you just want a clean slate for a new project. For these situations, you can use the /clear command.

Type /clear at the prompt and press Enter:

The /clear command starts a new session. Claude Code confirms this with a simple "(no content)" message, indicating that you're now in a fresh conversation. Your previous conversation isn't deleted—it's saved and can be accessed later using /resume. But in this new session, Claude Code won't have any memory of what you discussed before:

As you can see, Claude Code has no memory of your earlier messages about introductions or anything else you discussed in the previous session. This is useful when you want to switch contexts completely or when you're starting a new project and don't want Claude Code to be influenced by previous conversations.

When you're done working with Claude Code, you need to close the session properly. To do this, type /exit at the prompt and press Enter. The forward slash (/) tells Claude Code that you're using a special command rather than just chatting. You'll see a friendly goodbye message:

After this message, Claude Code closes, and you'll return to your regular terminal prompt. Your conversation is automatically saved, which means you can come back to it later. This is important because sometimes you'll want to take a break or work on something else, and you don't want to lose your progress.

Let's say you've exited Claude Code and now you want to continue where you left off. Maybe you were in the middle of working on a data visualization and you need to make some changes. Instead of starting a fresh conversation, you can resume your previous session.

To do this, start Claude Code again by typing claude in your terminal. Once Claude Code opens, type /resume at the prompt and press Enter:

You'll see a list of your previous conversations. In this example, there are two sessions available. The first one, "What did I just say?", was active 1 minute ago and contains 6 messages. The second one, "Claude Code Introduction", was active 2 minutes ago and has 9 messages. The arrow symbol (❯) points to the currently selected session at the top of the list.

At the bottom of the screen, you'll see navigation hints. You can press A to show all your projects, use / to search through your sessions, or press Esc to exit this menu without resuming anything. You can use the arrow keys to move between different sessions if you have multiple conversations saved. To resume the selected session, simply press Enter. Claude Code will load that conversation, and you can continue right where you left off.

This resume feature is incredibly useful when you're working on longer projects or when you need to step away and come back later. All your previous messages and Claude Code's responses will be there, so you don't have to explain everything again. You can also see that each conversation gets a descriptive title based on what you discussed, making it easy to find the right session when you have multiple conversations to choose from.

You've just learned the four essential commands for navigating Claude Code. Type claude in your terminal to start a new session. Use /clear when you want to start a fresh conversation while staying in Claude Code. When you're ready to leave, use /exit to close Claude Code properly. And when you want to return to a previous conversation, open Claude Code and use /resume to pick up where you left off.

These commands might seem simple, but they're the foundation for everything else you'll do with Claude Code. In the upcoming practice exercises, you'll get hands-on experience with launching Claude Code, having conversations, clearing chat history, exiting, and resuming sessions. You'll practice these steps until they feel natural and comfortable.

Remember, you're not expected to be an expert yet. Right now, you're just learning how to open the door, walk through it, start fresh when needed, and come back when you need to. In the next lessons, you'll start learning what Claude Code can actually do to help you with data visualization. For now, take pride in knowing that you can confidently navigate in and out of Claude Code whenever you need to!