Learn how to work together on the same project without stepping on each other's toes
What is a Branch?
A branch is like a parallel copy of your entire project where you can make changes without touching the main code.
Think of it like creating a backup of your game before you try a big new feature—if it breaks, your original is still safe.
Core Concepts
Main Branch
The "official" version of your project. In GitHub, this is usually called main or master. You keep it clean and working.
Feature Branch
A branch you create to work on one thing—a new feature, a bug fix, or a new game level. You name it something descriptive like add-multiplayer or fix-collision-bug.
Commit
A snapshot of your code at one moment in time. Every commit has a message describing what changed. Think of it like saving your game.
Pull Request (PR)
Your way of saying "Hey, I made some changes on my branch—can you review them and merge them into main?" It's like asking "Does this look good?"
Merge
Combining two branches. When your changes are approved, you merge your feature branch back into main. Both people's work comes together smoothly.
Conflict
When two people changed the same line of code in different ways, Git doesn't know which version to keep. Don't panic—GitHub helps you fix it.
Getting Started: Step by Step
1One of You: Set Up the Repo (Owner)
If you already have a GitHub repo, skip to step 3.
The project owner: Create a new repo on GitHub and add a README.md file. Then invite your collaborator to the repo (Settings → Collaborators).
2Both of You: Clone the Repo
Clone means "download a copy of the entire project and all its history."
git clone https://github.com/yourusername/your-repo.git
cd your-repo
Now you both have the same code on your computers, and Git is tracking it.
3You (Person A): Create a Feature Branch
You want to add a new feature. First, make sure you're on main, then create a new branch.
git checkout main
git pull origin main
git checkout -b add-score-system
Now you're on the add-score-system branch. Your changes won't affect anyone else.
✓ Naming tip: Branch names should be short and clear: add-lives-mechanic, fix-audio-bug, improve-ui-buttons. Use hyphens between words, no spaces.
4You (Person A): Make Changes & Commit
Edit your files, save them, and then tell Git to save them as a commit.
git add .
git commit -m "Add score system with multiplier logic"
You can make multiple commits as you work. Each one is a checkpoint.
5You (Person A): Push Your Branch
Push sends your branch to GitHub so your partner can see it.
git push origin add-score-system
Your branch is now on GitHub. Your partner's code is untouched.
6Your Partner (Person B): Works on Their Own Branch
While you're working, your partner does the exact same thing on their own branch.
git checkout main
git pull origin main
git checkout -b add-sound-effects
# ... make changes ...
git add .
git commit -m "Add victory and collision sounds"
git push origin add-sound-effects
Now you have two feature branches on GitHub, and you haven't interfered with each other at all.
✓ The golden rule: Never commit directly to main. Always create a feature branch first. This keeps main clean and lets you review each other's work.
Merging Your Changes Back
1Create a Pull Request (PR) on GitHub
After you push your branch, go to your GitHub repo. You'll see a prompt to "Compare & pull request." Click it.
Write a good PR description:
## What does this do?
Added a scoring system that tracks player points and applies
a 2x multiplier when the player gets 5 consecutive hits.
## How do I test it?
1. Click on a target 5 times without missing
2. Check that the score displays the multiplier correctly
3. Verify the score resets when you miss
## Checklist
- [x] Tested the feature myself
- [x] No console errors
- [x] Didn't break any existing code
2Your Partner Reviews the PR
They look at your changes, test them, and either approve or ask for fixes.
Things to look for:
Does the code make sense?
Did they break anything?
Are there any typos or obvious bugs?
Is it organized and readable?
If something needs fixing, they leave a comment, and you push a new commit to the same branch to fix it.
3Merge the PR
Once approved, click "Merge pull request" on GitHub. Your feature branch is now combined with main.
git checkout main
git pull origin main
Now both of you have the new feature on your computers.
Handling Merge Conflicts
If both people changed the same line, GitHub will say there's a conflict. Don't panic—it's easy to fix.
⚠ How conflicts happen: You and your partner both edit the same function in different ways on different branches. When you try to merge, Git doesn't know which version to keep.
GitHub will show you the conflict in the PR. Look for lines like this:
<<<<<<< HEAD
// Your version
function calculateScore() { return points * 2; }
=======
// Their version
function calculateScore() { return points + 10; }
>>>>>>> add-sound-effects
To fix it: Talk to your partner. Decide which code is better, or combine both ideas. Then delete the conflict markers and keep only the code you want.
function calculateScore() { return (points * 2) + 10; }
Commit this fix, and the conflict is resolved.
✓ How to avoid conflicts: Talk to each other about what you're working on. If you're both editing the same file, coordinate. Have one person finish and merge first, then the other person pulls the latest code.
Git Commands You'll Need
Checking Status & Branches
# See what branch you're on and what files changed
git status
# List all your local branches
git branch
# List all branches (local + remote on GitHub)
git branch -a
Switching & Creating Branches
# Switch to an existing branch
git checkout main
git checkout add-score-system
# Create a new branch and switch to it
git checkout -b add-new-feature
# Delete a branch (after it's merged)
git branch -d add-new-feature
Making & Saving Changes
# See all changes you made
git diff
# Add files to be committed
git add . # Add all files
git add filename.js # Add one file
# Save your changes as a commit
git commit -m "Clear message about what changed"
# See your commit history
git log
Syncing with GitHub
# Push your branch to GitHub
git push origin add-score-system
# Fetch the latest code from GitHub
git fetch origin
# Pull (fetch + merge) the latest main
git pull origin main
# See remote branches
git remote -v
Undoing Mistakes
# Undo changes in a file (before committing)
git checkout -- filename.js
# Undo your last commit (keep the changes)
git reset --soft HEAD~1
# Undo your last commit (discard the changes)
git reset --hard HEAD~1
⚠ Before using git reset --hard: This deletes your changes permanently. Only use it if you're absolutely sure.
Branch Simulator
Click through a realistic workflow to see how branches work. This shows commits, branches, and merges as they happen.