#-----In git Bash-----------
$ git clone https://github.com/git-ftp/git-ftp git-ftp.git
$ cd git-ftp.git && chmod +x git-ftp
$ cp ~/git-ftp.git/git-ftp /bin/git-ftp

#-----In your CMD----------
#Init a git repository on it:
git init
git add .
git commit -m "Initial commit"

#Configure you FTP:
git config git-ftp.user demouser
git config git-ftp.url ftp.example.com/demofolder
git config git-ftp.password demopassword

#Init the git-ftp client:
git ftp init

#Push your changes to FTP:
git ftp push

#Make your changes and commit:
git add someFile.html
git commit -m "Added someFile.html"

#Push your changes again and only what have changed is pushed:
git ftp push