Merge latest from git-basics into main.

git-basics/README.md

 # Git Basics
 
-## Creating a Repository
-
-  ### What's a repository ?
+## What's a repository ?
 
 A repository is a hierarchy of folders (directories) to store your project files and folders *as well as additional files used by Git to keep track of all operations performed on your project files and folders*.
 
@@ -10,6 +8,24 @@ A repository is a hierarchy of folders (directories) to store your project files
 
 Git is a distributed version management system. A specific project can be stored in multiple repositories. Usually, there is one reference repository used by all project contributors. All contributors have a local or work repository, which they initially cloned from the reference repository (more on this later).
 
+## What's a Branch ?
+
+In short: a branch is a name used to track the history of changes to files and folders over time, as a series of commits.
+A repository can manage as many branches as needed (more on this later). When working on a Git project, there is always a *current* branch. Git provides operations to create/remove/switch between branches.
+
+## What's a Commit ?
+
+In short: a commit is a set of changes to files or folders that we want Git to keep track of, such as:
+  - Addition a file or folder
+  - Modification of the contents of a file
+  - Removal of a file or folder
+  - Renaming of a file or folder
+
+Git provides operations to specify which files should be part of a commit.
+
+
+## Create Your First Repository
+
   ### [Log In to GitLab](/git-basics/media/gitlab-login.mp4)
 
   Log in to GitLab using your favourite account settings (GitLab, Google, GitHub, Twitter...)