Have a look at http://our.umbraco.org/projects/website-utilities/frontend-editing for details on the project usage.

When you've cloned the project, install an Umbraco 7 site in \Source\Site. Next install the current version of the package from Our (URL above) and follow the installation guide to enable frontend editing on your site.

Once you're done installing, open the Visual Studio solution from \Source\Solution and build it. The Umbracian.FrontendEditing project is configured to build to the bin folder of the site, so once built you should be good to go.

This project uses Grunt to building and preparing packages for Umbraco. If you're not familiar with Grunt, don't worry. You don't need to use it for contributing, as long as you're able to build the solution.