Before You Start: The Empty Computer

▸MODULE 1 / GETTING STARTED

Before we get started

You have not installed anything yet, have not touched a terminal yet, and maybe have never even seen one. That is exactly right. This lesson is the step before the first step: before you set up BuilderBob, we clear up the empty computer in front of you together. What is this black window that shows up in every tutorial? What does "repository" mean? And do you already have to decide between a subscription and API access right now? Five short blocks, and then you are ready for the actual setup in the next lesson.

I am deliberately taking the pace out of this. Nobody expects you to understand the terminal, folder thinking, and the subscription question in one minute. But a mental picture you sort out once carries you through the whole course, and after that, nothing feels foreign anymore, only new.

The terminal is just a text input field

The terminal looks like something out of a hacker movie: a black or dark background, white text, a blinking cursor. That look alone scares off a lot of people before they have even opened it. In reality it is the most harmless thing on the whole computer. A terminal is nothing more than a text input field, like a search box or a notes app, except the computer reads the lines you type as commands instead of text to save. You type, press Enter, and the computer answers with a few lines of text. That is all that happens, and nothing can break just from opening it and looking around.

How you open it depends on your operating system, and that changes with versions, so it is deliberately dated: (as of July 2026, check the exact menu items yourself if in doubt, or ask your AI directly about your version.)

• macOS: Press Cmd and the space bar at the same time, that opens Spotlight search. Type "Terminal" and press Enter. A new window opens, usually with a white or black background and your username on the left.
• Windows: Open the Start menu and type "PowerShell" or "Terminal". Both paths work for this course, PowerShell is the somewhat older one, "Terminal" the newer, bundled app. Click the top result.
• Linux: The shortcut varies by distribution, but Ctrl, Alt, and T at the same time is the most common. If that does not work, search your application menu for "Terminal" or "Console".

Open it once now, on your own machine, while you read this. Look at the window for twenty seconds. That is already the whole first step.

Folders, repos, and the three commands you actually need

A project you build with an AI always lives in a folder on your computer. Picture this folder as the home of an idea: every file that belongs to your invoicing tool or your landing page lives together in one place. The AI you work with in the terminal always only "sees" the folder it currently stands in, the same way you only see the room you are currently in. That is why the first question whenever something looks off, later on, is often: which folder am I actually working in right now?

A repository, or "repo" for short, is at its core exactly such a project folder, just with an extra memory: it remembers how the files changed over time, like a diary for code. For now, one picture is enough: repo equals project folder with history. You do not need to know more than that right now, BuilderBob explains the rest once you actually need it.

Three commands are enough to find your way around this home, and all three are short enough to remember right away:

• pwd shows you which folder you are currently standing in (the letters stand for "print working directory"). Type it, press Enter, and you see a path like an address.
• ls shows you what is inside that folder, meaning the list of files and subfolders.
• cd followed by a folder name takes you into that folder, the same way clicking a folder in Finder or Explorer does, just from the keyboard.

A small example: you type pwd and see that you are standing in your user folder. You type ls and see a folder called "Projects" in there. You type cd Projects and are now inside it, which you can confirm again with pwd. That is the whole mechanic, everything else just builds on it.

Why this matters: your AI in the terminal always works "in a folder", exactly like you just did. Once you know where you stand, you also understand why it sometimes cannot find a file that lives somewhere else.

Installing: follow the official path, not an old tutorial

For the tools in this course, most of all the agentic CLI you set up in a later lesson, there are usually two installation paths: a native installer, meaning a ready-made package you download and double-click, and an installation via a package manager like npm or Homebrew, meaning a tool that installs programs directly through the terminal and keeps them up to date.

Which path is currently recommended changes, because providers and tools keep evolving. So the one rule that stays stable over time: follow the official installation path from the provider's own documentation, not a video or forum post that might already be outdated. And if you are unsure which path is right for you, ask your AI in the app builder or in a chat exactly that, before you install anything. (As of July 2026, the concrete installation paths change, the official docs of each provider are the reliable source, check for yourself.)

Subscription or API access: a decision you make once

Before you set up an AI tool for this workbook, one question comes up that sounds technical at first glance but is really just an everyday decision: do you pay a fixed monthly rate (subscription), or do you pay per use (API, meaning pay-per-token)?

A subscription is like a gym membership: a fixed rate every month, no matter how often you show up, predictable, good if you work regularly. API access, meaning usage-based billing "per token" (tokens are, roughly, the small text chunks an AI model processes, and they are also the billing unit), is more like a taxi: you only pay for what you ride. That is ideal for a first look and for irregular use, but it can end up more expensive than a subscription if you work intensively, every day.

For your path through this course, either one is enough: an entry-level subscription with one of the big providers, or a moderate balance on an API account. There is no single right answer here, only the one that fits your usage pattern. If you build almost daily, the subscription tends to pay off faster. If you are just trying it out for a weekend or two, a small API balance is often the cheaper entry.

What I deliberately do not give you are concrete prices. They change too often to put in a workbook meant to accompany you for a while. (As of July 2026, you always find current prices on the pricing page of the respective provider, check there yourself before you decide.) What matters is only that you make this decision before you dive into the next lesson, not halfway through building.

The three most common setup mistakes

Almost everyone new to this trips over one of these three small things. Knowing them ahead of time costs you a minute instead of a frustrating hour.

First, working in the wrong folder. You believe you are in your project folder but are actually somewhere else, and suddenly files are missing or show up in the wrong place. The fix is the command you just learned: type pwd and see where you really stand. That is almost always the first move whenever something looks strange.

Second, "command not found" right after a fresh install. You just installed a tool, type its name, and the terminal says it does not know the command. That is almost always because your current terminal window has not yet "seen" the freshly installed command. The simplest fix: close the terminal window completely and open a new one. Behind this sits the so-called PATH, a list of places your computer looks for commands, in plain terms a kind of table of contents that only gets re-read when the window restarts. If that does not help, pass the exact message on to your AI and let it guide you instead of guessing yourself.

Third, a missing foundation like Node, or missing permissions. Some tools need another program running in the background (Node.js, for example, a runtime that many CLI tools need to work), or your machine does not have the permissions needed to install something. Here too the same rule applies as everywhere in this course: copy the error message in full, word for word, and hand it to your AI. The message almost always already contains what is missing, you just have to pass it along.

Before I continue, here is my current status:

Terminal: (open, yes or no, and on which operating system, Mac,
Windows, or Linux)
Result of pwd: (whatever the command shows me right now)
Subscription or API access: (what I decided, and why)

Tell me honestly whether anything about this status is in the way of
an installation, or whether I am ready to continue now.

The honest assessment

None of this is something you need to memorize. You will type pwd, ls, and cd so often in the coming lessons that they will sink into your fingers without you consciously thinking about them. And the subscription-or-API question is not one you lock in forever: if you notice after a few weeks that the other option fits you better, you simply switch. None of this is set in stone.

What this lesson really gives you is a calm head for the next step. The terminal is not an exam room where you can do something wrong just by looking at it. And when a message shows up that you do not understand, that is not a setback, it is exactly the next question for your AI. With this status, you now move on to the next lesson and set up BuilderBob, your AI building companion for the rest of this course.