How to mod locally?

[supashaka]

I couldn't get a specific River City Girls mod I found to run and I can't figure out why. Nor could I find other any useful mods for this game. But my question is for games in general. I've text edited some game's files in the past but didn't know what to do with other files.

I really want to find some way of displaying the damage values through editing my own local files, I can edit River City Girls\RiverCityGirls_Data\StreamingAssets with a text editor but I don't know where to look to display damage. which file do I need to edit? I know how to open .json files but how do I open and understand/edit like assets, bank, and 'file' extensions? When I open River City Girls\RiverCityGirls_Data\Managed\Assembly-CSharp.dll with a code editor, does NUL mean true or false, if so how do I write true? Could I just add 'displayDamageOnHit' or "displayhitDmg"? Where in the doc would I place, and what would I add to make it work?

If anyone has useful links (in addition to specific advice) which would explain in simple steps I'd appreciate it, thank you.