Need help, trying to apply a plug-in to better mod for 'Idol Manager'

[ImperialForce9]

https://steamcommunity.com/sharedfiles/filedetails/?id=2976384244
Trying to use this mod and it requires stuff from IM-HarmonyIntegration

Link to IM-HarmonyIntegration: https://github.com/ui3TD/IM-HarmonyIntegration

This other mod https://steamcommunity.com/sharedfiles/filedetails/?id=3102983863 is used as a little "yeah IM-HM is properly applied" check

I understand downloading the IM-HM file linux version from github. Though I believe Im fudging at step 4.
The 'setting up permissions' section, you're asked to 'add execution permission' to a "run_bepinex.sh" file using

'chmod u+x run_bepinex.sh'

I did the steps and when trying to run the game, it crashes on startup. Where am I going wrong?