Introduction to Git and GitHub – Part 3

In this final part of the Git and GitHub introduction tutorial, you will learn to master GitHub’s advanced collaborative features, such as issues, branches, and pull requests, to effectively manage your contributions and those of others in a GitHub project.

Requirements#

• Have completed Introduction to Git and GitHub – Part 2.
• Have some basic knowledge of using a terminal.

Final Goal: The Treasure Mine#

Throughout this introduction, we illustrated our explanations and manipulations using the repository-mine. In general, a mine is created to extract ores, veins, or treasures… Wouldn’t it be a good idea to add a treasure to the repository-mine to give it value? With this in mind, I created a file in the repository called Our_Treasure.md:

# Our Treasure

* "The limits of imagination are those we impose on it."

For now, it is not very full, I’ll admit… But it is a phrase that is close to my heart, an important principle on which I base my thinking. Since this phrase has value to me, I can consider it a treasure. It is the first stone of a much larger treasure: the next ones are up to you to add!

The final goal is to fill this shared treasure with your personal touch: it can be a quote you particularly like, a sentence that inspires you, thoughts or words that motivate you daily and that you want to share with others. This file will thus become the core of the repository-mine treasure, enriched by everyone’s contributions.

Issues#

An issue is a discussion space associated with a repository. Specifically, it allows you to report a bug, propose an improvement, describe a problem, or ask a question. This helps contributors have a global view of the repository’s problems and goals and track their resolution throughout the project.

On GitHub, all I have to do is click on the “Issues” tab in my repository, then on “New Issue”:

See the issue on GitHub.

In the image above, you can see the different features of an issue:

• Title: “Grow our treasure.” The title summarizes in one sentence what the issue is about.

• Description: It provides more detail about the issue’s context, explaining what is expected and possibly indicating constraints or suggestions.

• Labels: They allow categorizing the issue. Here, the enhancement label indicates the issue aims to improve the base repository. The good first issue label shows that this is ideal for someone making a first contribution.

The next step is to modify the relevant files to enrich the shared treasure. However, since the repository was created by me, you cannot directly modify its contents. Rather than granting write access to everyone individually, GitHub offers an alternative mechanism: the fork.

Forks#

To illustrate how to create a fork, a new contributor is introduced: Chromatistí.

Chromatistí!

“Forking” a repository means creating a complete copy of a repository in your own GitHub account. This copy, the fork, belongs to you: you can make any modifications you want. This is the most common way to contribute to a project without being the original owner.

Forking a repository is like having an identical mine where you can do anything!

• To create a fork, Chromatistí goes to my repository and clicks the “Fork” button:

• Chromatistí then checks the fork information. Default information comes from the original repository but can be modified:

• Chromatistí clicks “Create fork” and finally obtains a repository-mine identical to the original (notice the icon next to the repository name):

Branches#

A branch is a parallel line of development that allows working on changes without affecting the main project version. Branches are useful when testing new ideas, fixing bugs, or developing new features without impacting the original project. Here, the branch will be used to modify the Our_Treasure.md file before integrating it into the main branch.

Creating a branch#

The command git checkout -b <branch_name> creates a new branch. For example, if Chromatistí opens a terminal on his local repository and runs:

git checkout -b my-treasure

a new branch called my-treasure is created and he places it there directly. The Our_Treasure.md file can now be modified without affecting the main branch:

# Our Treasure

* "The limits of imagination are those we impose on it."

* "A picture is worth a thousand words." – Confucius (Printer’s Ink, 1921).

To apply the changes in Git, you must use the same commands as in the previous part. The only difference is adding the --set-upstream origin <branch_name> flag to git push:

git add Our_Treasure.md
git commit -m "Adding my treasure to the common good"
git push --set-upstream origin my-treasure

The branch and its associated changes are now visible on GitHub.

Branch change is immediately visible in the main interface.

Here we see the active branch is "my-treasure" and the commit has been recorded.

Use git checkout <branch_name> to switch branches. For example, to return to the main branch:

git checkout main

You will then see that the Our_Treasure.md file has been restored to its original state.

You are here!

Try switching between branches to see the different changes!

Merging branches#

Merging branches combines changes from two branches into a unified project version. Use git merge <branch_name> to do this.

With Chromatistí, this would be:

git checkout main  # switch to main branch
git merge my-treasure

Changes from the my-treasure branch now appear on the main branch:

# Our Treasure

* "The limits of imagination are those we impose on it."

* "A picture is worth a thousand words." – Confucius (Printer’s Ink, 1921).

Illustratively: merging the two train branches to have only one mine.

After merging a branch, you can delete it with git branch -d <branch_name>. For Chromatistí:

git branch -d my-treasure

Since the changes were made locally, they need to be pushed to the remote repository for them to take effect:

git push

You now have your treasure in the mine! But remember, changes were made in your fork. The final step is to include these changes in the main repository. This is the role of a pull request.

Pull Requests#

A pull request is a key GitHub mechanism that proposes merging changes from one branch into another, while providing a space for discussion and review before integration.

It's like asking to merge the two mines into one.

The process happens on GitHub:

• In his fork, Chromatistí clicks “Contribute”, then “Open pull request”, opening an interface to write a title and description:

For this exercise, he can write “Pull request for issue …”. For which issue? There are two ways to specify:

• Click the “Reference” button as shown on the above image.
• Type # in the description field.

In both cases, a list of issues and previous pull requests appears; just select the relevant issue (here, issue #1).

Adding a description and references provides context for the changes made, making it easier for the original repository owner to understand them.

Once the pull request is created (“Create pull request”), just wait for a contributor (in this case, me) to approve it:

And there you have it!

Going Further#

Summary Table of Commands#

As in the previous part, this table summarizes all commands covered in this tutorial and their purpose. Keep it handy when getting started with Git!

Credits#

• Writer: Ousmane THIONGANE
• Latest update: January 2026
• Reviewers: