I'm super new to GIT, and thought I could create a simple test commit/push. In the process I ended up with a mess shown in the attached image.
The question is, what GIT commands do I need to invoke to remove all the stuff above the red arrow and leave origin/master at the point where the red arrow is?
I don't care about any files in my local clone of the repository. When this mess is fixed, I can just re-clone.
Assuming you're on your local version of master, I'd go with:
git reset --hard 4c5222c0
That brings your local repo to the hash of the commit pointed by the red arrow.
Then you can force push to master, for example like that:
git push origin +master