Go to the mod workshop description, scroll down and find the configuration section. With Mod Config Menu, go to General > Language and scroll the languages until you see Chinese (Simple). If editing the mod config directly, replace

["Language"] = "en_us",

with

["Language"] = "zh_cn",

"All configuration except the language setting can be changed with it in game." is false/old info which has been changed in the source and will be changed here when the mod is updated.

thanks!!