The Git index, along with the need to use the "git add" command before performing a commit, is often a source of confusion for beginners. These "git add" examples will make things clear.

How to undo a Git add To unstage a file in the Git index and undo a git add operation, any of the following three commands will work, although only the git restore command is recommended: ...

Jack Wallen shows how to use the .gitconfig file for global git configurations and a more efficient developer setup.