First, you create your branch locally:
git checkout -b <branch-name>
The remote branch is automatically created when you push it to the remote server. So when you feel ready for it, you can just do:
git push <remote-name> <branch-name>
Where <remote-name> is typically origin, the name which git gives to the remote you cloned from. Your colleagues would then just pull that branch, and it's automatically created locally
