I wasn't sure how to do step 2 ("Create a local branch of the github repository as well called github-master"). After looking it up I followed the instructions from https://stackoverflow.com/a/14383288, i.e. something like this:
- git remote add fork https://github.com/zotero/translators.git
- git fetch fork
- git checkout -b zotero fork/master
I don't know if that's they way you're supposed to do it, but it may be worth adding some clarification either way.