If your folder has report_final.xlsm, report_final2.xlsm and report_final_REAL.xlsm, you already understand why Git exists. It records every version of your files, who changed what, and lets you go back.

The four ideas

• Repository — a folder Git is tracking.
• Commit — a saved snapshot with a message (“Fix VAT rounding”).
• Branch — a parallel line of work, so experiments do not break the main version.
• Merge — bring a branch’s changes back.

First project

git init                         # start tracking this folder
git add .                        # stage all files
git commit -m "First version"    # save a snapshot
git log --oneline                # list snapshots
git checkout -b new-report       # start a branch
# ...edit files...
git add . && git commit -m "Add region chart"
git checkout master              # back to the main line
git merge new-report             # bring the work in

Undo mistakes

git diff                         # what changed since the last commit
git checkout -- macros.bas       # throw away edits to one file
git revert <commit-id>           # undo an old commit safely

Put your repository on GitHub or GitLab for a free off-site backup and easy sharing.