git clone https://github.com/<username>/missingmaps.github.io.git
cd missingmaps.github.io
git branch
git checkout -b <newbranchname>
git add -A
git commit -am "your commit message"
git push origin <newbranchname>
git checkout <branchname>
so: git checkout publish
git pull origin <branchname>
so: git pull origin publish
if your GitHub version of publish is not up-to-date with the core MissingMaps repo, you can either add upstrem references (not shown here) or do a Pull Request (on GitHub between the main repo publish branch and your publish branch