Welcome to overleaf, (formerly writeLaTeX) --- just edit your LaTeX on the left, and we'll compile it for you on the right. If you give someone the link to your project, they can edit at the same time. If you create a free overleaf account, all your projects will be saved. See the help menu above for more info. Enjoy!
My thanks to Dana Ernst of Northern Arizona University for sharing his template with me. This is largely his work.