When working with programming languages, which `ftd` is after all, or to do web development in general, most people install programming language toolchain, and some editor on their laptops. We can also do it completely online, without installing anything on your machine/laptop etc. We at `fastn` support both, and recommend you learn both as there are advantages to both working on your laptop and working in online editor.

If you are ready we can start by launching our codespace. You should see a green button, "Code", if you click on it this pane opens.

Before we begin let's try to develop some mental model or intuition for a codespace. Codespace is a linux machine. It is actually a virtual machine, but you can ignore this detail. Imagine when you hit that button Github has allocated one machine from their pool of machines to you. This is why this feature is paid feature. They are giving you a machine with RAM, CPU and harddisc. When the machine starts up, Github installs an operating system for you. The operating system contains a programming editor, a version of [`vscode`](https://code.visualstudio.com) if you are curious. They also install `git`, since your code is stored in a "git repository", and we will be using `git` a lot in this book. And they finally "clone" your git repository to that machine. In the context of `git`, `clone` is a fancy word for download. Once this machine is ready you can start interacting with it in the browser, which we will see later. The important thing is if you close your browser, the machine will keep running for a short while, and then go in a "standby" mode. In this mode all changes you do are kept, and you can restart your codespace from the standby mode, and start using again. Remember, one codespace is equal to one machine. You can create as many codespaces as you want. Even for the same repository. If you create more than one codespace for the same repository you will have to remember on which codespace, or machine you did what change. One important bit to note about codespaces is that *only the person who started the codespace has access to it*. In general it is not a great idea to keep stuff in codespaces for long periods of time. The way to work with codespaces is to start a codespace, get your code there, modify the code to your satisfaction, and then "push" or store your code back in the repository. All your changes should move to your repository, which should be your source of truth about all changes. Even changes that you are not fully satisfied with, changes that are work in progress can be stored in the repository in what is called "branches" which we will read about later, but your goal should be to not keep stuff in codespaces and keep "pushing" things to your repo, and then you can delete the codespace if you want. Why delete? So it does not accumulate cruft. If you keep everything important in the repository you can start again within seconds, but if you keep stuff on some machine it will start to become "source of truth" for somethings, "oh this file in repo, this is not the latest version, the latest version is in that codespace that only I have access to". What if you have more than one code spaces? What if you also sometimes download and edit content on your laptop? Where is the latest version of the file? Imagine you are working with 5 people, everyone has their codespace and latops, it starts to become a mess very soon. Keeping repository as the single shared source of truth is a good practice that this book advocates.

If you clicked on the big green "Create codespace on main" button in the previous step, you should see something like this:

Note: We have intentionally not configured codespace to auto install `fastn` for you so you manually carry out the installation step, and gain confidence that installing `fastn` is quite easy and you can do it on other machines. To install `fastn` you have to run the following command:

Now that `fastn` is installed, we have to run it. We are going to run the `fastn serve` command to run your website inside codespace.

To open it in browser you can click on the green "Open in browser" button. Since the pop goes away you can also do this manually. Switch to the PORTS tab next to TERMINAL, right click on the single row displayed there, and select "Open in browser".

What you did in this section is quite a bit. You used a feature by Github to launch a machine in cloud for you. You connected with this machine and saw your repository content is already there. You then installed `fastn`, and run a website on that cloud machine. And finally you previewed the website in the browser. Congratulations, you are making good progress. You are going to [edit your website next ->](/book/first-edit/).