To do full development with 2sxc, you need to setup your development environment to match the recommended setup. This is because various part require automation to work efficiently. For example...
- eav-ui and 2sxc-ui has automation tasks which compile the JS and copy it into a predefined dist-folder in the 2sxc project so that you can test it efficiently
- the languages and icons are updated back to github and 2sxc-ui will retrieve the defined version using bower
- the eav-project contains a full solution which compiles both 2sxc and eav for more efficient work style
I must appologize that this isn't perfectly documented, there's just so much to do. You'll find the instructions here in a StackOverflow answer.