EditMe's Modules are all written using the API. Once installed into your site, the complete source code of every page installed as part of a module can be viewed by an administrator. Installing a module, studying how it works, and making changes is an excellent way to learn EditMe's API and template language interactively.
If you break a module while making changes, simply reinstall it. Your customizations will be saved as previous versions of the pages/attachments that are over-written by the installation.