checkout branch from another fork code example
Example: fetching a forked branch
$ git remote add theirusername [email protected]:theirusername/reponame.git
$ git fetch theirusername
$ git checkout -b mynamefortheirbranch theirusername/theirbranch
$ git remote add theirusername [email protected]:theirusername/reponame.git
$ git fetch theirusername
$ git checkout -b mynamefortheirbranch theirusername/theirbranch