git Warm-Up how to start a repo from scratch? git init local method on GitHub git clone and either git push --force or git pull methods how to revert mistakes? git revert vs. … git reset vs. … git reset --hard vs. … git restore how to go to a specific point in history? git checkout SHA ⟶ DETACHED HEAD problem interaction with branches git gui: building commits along the way interactively (for the mess around type of workflows) The Open Source model remotes: pull, push, fetch, merge GitHub: forks, branches and PRs: important ➔ explain fork vs. clone!!! strategies for keeping your fork up-to-date: your main and upstream's main, short-lived and long-lived topic branches a more thorough and detailed explanation can be found on the Numpy Contributor's Guide. This guide can be adapted to your own needs, see gitwash.