Walk through git/git-review/gerrit process for MediaWiki development: you'll write. commit, and "push" a sample diff, you'll comment on it, and you'll review it and reject it or merge it into trunk.

Find me half an hour beforehand in IRC (#mediawiki on FreeNode) so we can get your account set up before the training, and so I can give you the Google+ hangout address and you can get setup.

Reference material: https://www.mediawiki.org/wiki/Git/Workflow

If you can do Google+ Hangout (you don't have to enable your webcam or audio) then you'll see my screen as I show you these steps. If you can only do IRC then please let me know and I'll separately schedule some IRC trainings.