create_git_branch_based_on_another

It's a set of scripts he created for that workflow.

But to answer your question:

$ git checkout -b myFeature dev
Creates MyFeature branch off dev. Do your work and then

$ git commit -am "Your message"
Now merge your changes to dev without a fast-forward

$ git checkout dev
$ git merge --no-ff myFeature
edit

Now push changes to the server

$ git push origin dev
$ git push origin myFeature