# clone, create and change to branch development
git clone git://the/open/source/project.git
git checkout -b development
# make changes and commit
git add ...
git commit -m '...'
# several commits later, create a branch named staging and change to it
git checkout -b staging
# after testing, create a branch named production and change to it
git checkout -b production
# syncing ( assuming the remote to be named origin and the branch is named master )
git checkout master
git fetch origin master
git merge origin/master
# repeat the process