Instructor guide

Detailed schedule

We share this as a good starting point for planning:

Why we teach this lesson

In order to collaborate efficiently using Git, it’s essential to have a solid understanding of how remotes work, and how to contribute changes through pull requests or merge requests. The git-intro lesson teaches participants how to work efficiently with Git when there is only one developer (more precisely: how to work when there are no remote Git repositories yet in the picture). This lesson dives into the collaborative aspects of Git and focuses on the possible collaborative workflows enabled by web-based repository hosting platforms like GitHub.

This lesson is meant to directly benefit workshop participants who have prior experience with Git, enabling them to put collaborative workflows involving code review directly into practice when they return to their normal work. For novice Git users (who may have learned a lot in the git-intro lesson) this lesson is somewhat challenging, but the lesson aims to introduce them to the concepts and give them confidence to start using these workflows later when they have gained some further experience in working with Git.

Intended learning outcomes

By the end of this lesson, learners should:

  • Understand the concept of remotes

  • Be able to describe the difference between local and remote branches

  • Be able to describe the difference between centralized and forking workflows

  • Know how to use pull requests or merge requests to submit changes to another projects

  • Know how to reference issues in commits or pull/merge requests and how to auto-close issues

  • Know how to update a fork

  • Be able to contribute in code review as submitter or reviewer

Interesting questions you might get

  • If participants run git graph they might notice origin/HEAD. This has been omitted from the figures to not overload the presentation. This pointer represents the default branch of the remote repository.


  • The centralized collaboration episode is densest and introduces many new concepts, so at least an hour is required for it.

  • The forking-workflow exercise repeats familiar concepts (only introduces forking and distributed workflows), and it takes maybe half the time of the first episode.

  • The “How to contribute changes to somebody else’s project” episode can be covered relatively quickly and offers room for discussion if you have time left. However, this should not be skipped as this is perhaps the key learning outcome.

Preparing exercises

Exercise leads typically prepare exercise repositories for the exercise group (although the material speaks about “maintainer” who can also be one of the learners). Preparing the first exercise (centralized workflow) will take more time than preparing the second (forking workflow). Most preparation time is not the generating part but will go into communicating the URL to the exercise group, communicating their usernames, adding them as collaborators, and waiting until everybody accepts the GitHub invitation to join the newly created exercise repository.

Live stream:

  • Create the centralized exercises in an organization (not under your username) so that you can give others admin access to add collaborators. Also this way you can then fork yourself if needed.

  • For CR workshops, the exercises were placed under

  • We have created two versions of each a day in advance to signal which one might end up being discussed on recording/stream:

    • centralized-workflow-exercise-recorded

    • centralized-workflow-exercise

    • forking-workflow-exercise-recorded

    • forking-workflow-exercise

  • Protect the default branch of the two centralized-* repositories.

  • We create a organization team, stream-exercise-participants. The centralized workflow exercise repos have this team added as a collaborator (not forking - they fork so they don’t need write access there).

  • We have collected usernames of people who want to contribute via issues on GitHub. Make a fifth repository, access-requests, create a sample access request issue there, and have learners make a new issue in that repository. The day before

    • Why a fifth repository? So that learners don’t get emails from all other access requests once they get added to the team

    • Sample text:

      On Thursday we will all practice how to collaborate using Git/GitHub
      and one ambitious thing we will try is to collaborate with
      participants following via stream. This does not apply to teams and
      exercise groups who will create their own exercise repositories and
      these groups can ignore the rest of this section.
      For this to work we will need to give you access to a practice
      repository.  This is option, you could just watch instead. We delete
      these repositories after the workshop and will not use your username
      for anything other than this exercise.
      If you would like to participate in this, could you please open an
      issue here.  Give any title like "please add me" and then click
      Example for how I requested access:

Typical pitfalls

Difference between pull and pull requests

The difference between pull and pull requests can be confusing, explain clearly that pull requests or merge requests are a different mechanism specific to GitHub, GitLab, etc.

Pull requests are from branch to branch, not from commit to branch

The behavior that additional commits to a branch from which a pull request has been created get appended to the pull request needs to be explained.

Other practical aspects

  • In in-person workshops participants really have to sit next to someone, so that they can see the screens. From the beginning.

  • Emphasize use of git graph a lot, just like in the git-solo lesson.