Instructions for modders forking this:
Follow the instructions outlined by Darloth in issue #20, located at https://github.com/Alarcarr/Rising-Star/issues/20.
Create a .steam file containing the line "355873534" in the root directory of your working copy. (Where the repository's .git folder is located.) This will prevent you from accidentally pushing your work to the Workshop instead of GitHub.
Download the ABEM Modding Toolkit, either from the Steam Workshop or by pulling the latest #STEAM commit from https://github.com/DaloLorn/SR2Mods/tree/ABEMTool. It's got a few useful tweaks for the mod editor that could come in handy.