Visual Studio Code is a free and open-source code editor created by Microsoft. It is flexible, extensible, and works on many different platforms. We'll use it to work on our React Native application. To install it:

• Windows: Download the app from here: https://code.visualstudio.com
• Chromebook: Follow the "Download VS Code" step of the tutorial here: https://medium.com/@jacoboakley/web-development-with-a-chromebook-react-environment-setup-46173b1dc375

Node.js is a tool that lets programmers use JavaScript to build fast and efficient servers for websites and applications. It has two particularly helpful features:

1. The npm and npx command-line tools that will help us install many tools we'll need quickly and easily
2. A runtime, which will run the code we write on our computers. To install it:

• Windows: Go to this website: https://nodejs.org/en/download/ and click the "Windows Installer" button
• Chromebook: Follow the "Install Node.js" step of the tutorial here: https://medium.com/@jacoboakley/web-development-with-a-chromebook-react-environment-setup-46173b1dc375

Run npx create-expo-app [APP NAME] (e.g., npx create-expo-app demo-app) to create an empty React Native application.

In the terminal, navigate to the demo-app folder in this repository (e.g., cd demo-app).

Run npm-install in the demo-app folder to ensure all the libraries the app is using are up-to-date.

Run the app using one of the following commands:

• To run the web version: npm run web
• To run the iOS version: npm run ios
• To run the Android version: npm run android

Git is a tool that helps software developers work together on projects by keeping track of changes to the code (kind of like you use Google Docs to work together on documents). It's a command-line application, so we need to install it before we can use it:

• Windows: install Git by downloading the appropriate installer here: https://git-scm.com/download/win
• Chromebook: git should be automatically installed when you install Linux (check out this tutorial for more details https://www.geeksforgeeks.org/how-to-install-git-on-chrome-os/)

Let's say you made a change to one of the app files locally, to "publish" your changes so that the rest of the team can see them, you need to run a couple of commands:

1. git add -a: tells git that you want to publish all of the changes you made
2. git commit -m "[A SHORT DESCRIPTION OF THE CHANGES]": describes the changes you made so that the rest of the team knows why you made them
3. git push origin main: actually publishes (or pushes) your changes to GitHub where the rest of the team can see them

Sometimes, you might get an error that looks something like this:

error: failed to push some refs to 'https://github.com/REDACTED.git'
hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Integrate the remote changes (e.g.
hint: 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

This error happens when another member of your team published changes to GitHub and you haven't pulled them yet. To fix this, run git pull origin main (see "Pulling Changes" section below for more details) and then try running git push origin main again.

Let's say one of your teammates changed some files and pushed them using the steps above, and now you want to download them to your computer. To do so, simply run git pull origin main. This will "pull" all of the files on GitHub to your local computer.

Sometimes when pulling changes, you may get a "conflict" error. This happens if you and a teammate have made conflicting changes to the same part of a file, and now git doesn't know which changes to keep.

For example, say you and your teammate both created the same file called todo.txt. Your todo.txt file looks like this:

 - do homework
 - take a nap

while your teammate's todo.txt file looks like this:

 - make lunch
 - walk dog

When you run git pull origin main, you'll get a "conflict" error and the file on your computer will now look something like this:

<<<<<<< HEAD
 - do homework
 - take a nap
=======
 - make lunch
 - walk dog
>>>>>>> q4q20joirnf0a

You will have to decide whether you want to only keep your own changes, only keep your teammate's changes, or keep both changes. You can then edit the file to reflect your decision. Then, you can follow all three steps from the "Pushing Changes" section to commit and push the file.