Git is a distributed version control system that tracks every change you make to your code. Think of it as an “unlimited undo” button for your entire project — you can jump back to any point in time, see who changed what, and safely experiment without breaking things.

GitHub is a cloud platform built on top of Git. It hosts your repositories (projects) online, adds collaboration tools like pull requests, issues, and actions, and serves as the world’s largest developer community. Whether you’re building a personal project or contributing to open source, GitHub is where modern software lives.

Step A — Install Git

Download Git from git-scm.com. On macOS you can also use Homebrew; on most Linux distros, Git comes pre-installed.

# Check if Git is installed
git --version

# macOS with Homebrew
brew install git

# Ubuntu / Debian
sudo apt install git

Step B — Create a GitHub Account

Head to github.com and sign up for a free account. Choose a username you’ll be proud of — it becomes part of your public developer identity.

Step C — Configure Git Locally

Tell Git who you are. This information gets attached to every commit you make.

git config --global user.name "Your Name"
git config --global user.email "you@example.com"

# Verify your settings
git config --list

Step D — Set Up SSH Authentication (Recommended)

SSH keys let you push and pull code without typing your password every time.

# Generate a new SSH key
ssh-keygen -t ed25519 -C "you@example.com"

# Copy the public key to your clipboard
cat ~/.ssh/id_ed25519.pub

# Then paste it into GitHub → Settings → SSH Keys

A repository (or “repo”) is a project folder that Git tracks. You can create one on GitHub’s website, from the command line, or both.

Option 1 — Create on GitHub, Clone Locally

git clone git@github.com:your-username/my-project.git
cd my-project

Option 2 — Start Locally, Push to GitHub

# Create a folder and initialize Git
mkdir my-project && cd my-project
git init

# Create a file and make your first commit
echo "# My Project" > README.md
git add README.md
git commit -m "Initial commit"

# Link to GitHub and push
git remote add origin git@github.com:your-username/my-project.git
git push -u origin main

Day-to-day Git boils down to a simple loop. Understanding this cycle is the single most important thing to internalize.

# 1. Check what's changed
git status

# 2. Stage specific files (or all changes)
git add index.html style.css
git add .          # stage everything

# 3. Commit with a descriptive message
git commit -m "Add responsive nav bar"

# 4. Push to GitHub
git push

Branches let you work on features, fixes, or experiments in isolation without touching the stable main branch. This is what makes team collaboration possible — everyone works on their own branch, then merges when ready.

# Create and switch to a new branch
git checkout -b feature/user-auth

# See all branches (* = current)
git branch

# Switch between branches
git checkout main

# Merge a branch into main
git checkout main
git merge feature/user-auth

# Delete a branch after merging
git branch -d feature/user-auth

A Pull Request (PR) is GitHub’s way of saying “Hey team, I’ve got changes ready — please review and merge them.” It’s the heart of collaboration on GitHub.

Creating a Pull Request

Contributing to Other Projects (Fork & PR)

Want to contribute to someone else’s open-source repo? The workflow is: Fork → Clone → Branch → Change → Push → PR.

# 1. Fork the repo on GitHub (click "Fork" button)
# 2. Clone YOUR fork
git clone git@github.com:your-username/forked-repo.git

# 3. Add original repo as "upstream"
git remote add upstream git@github.com:original-owner/repo.git

# 4. Create a branch, make changes, push to YOUR fork
git checkout -b fix/typo-in-readme
# ... make changes ...
git push origin fix/typo-in-readme

# 5. Open a PR from your fork to the original repo

When other people push changes, you need to pull them down. When your branch falls behind main, you need to rebase or merge. Here are the essential commands.

# Pull the latest changes from the remote
git pull

# Pull with rebase (cleaner history)
git pull --rebase

# Update your feature branch with latest main
git checkout feature/my-work
git rebase main

# If you're working on a fork, sync with upstream
git fetch upstream
git rebase upstream/main

Handling Merge Conflicts

Conflicts happen when two people edit the same line. Git will mark the conflicts in your files with <<<<<<< markers. To resolve them:

1. Open the conflicted file and find the conflict markers.
2. Choose which version to keep (or combine both), and delete the markers.
3. Stage the resolved file with git add and continue.

# After fixing the conflict in your editor:
git add conflicted-file.js
git rebase --continue
# or if merging:
git commit

Issues

GitHub Issues are your project’s task tracker. Use them to report bugs, request features, or track to-dos. You can label them, assign team members, and link them to PRs with keywords like Fixes #42 in your commit message.

GitHub Actions (CI/CD)

Automate testing, building, and deploying your code. Actions run workflows triggered by events like pushes or PRs. A workflow is defined in a YAML file inside .github/workflows/.

GitHub Pages

Host static websites directly from a repo — perfect for portfolios, documentation, and project landing pages. Enable it in your repo’s settings under “Pages.”

The .gitignore File

This file tells Git which files and folders to ignore — things like node_modules/, environment files (.env), and build artifacts. GitHub provides templates for every major language at github/gitignore.

README.md

Your repo’s front page. A great README includes a project description, installation instructions, usage examples, and contribution guidelines. It’s the first thing visitors see — make it count.