Overview of Git.
Think that the git is a tree that has several branches, the main root is called Master and the branches are called Branch.
1- When we create a git, a Master is automatically created, also named HEAD. .

2- You can build branches:

Notes:
- By following this tutorial, you'll understand, but think git is a tree.
- Always read the git commands that the terminal says, and git always gives advice: where is wrong, what to do.