Lo-Fi Games

Right hello everyone, I owned Kenshi since it came out on steam and I was thinking of getting into the modding scene since I am studying to become a Game Artist and therefore I have several questions. First off, how do I go about making re-texturing already made items such as Heart Protector, Samura...

Anyone know?
If so please teach me

How do you change the state of the weapon etc all weapons i created so far is only rusty and im wondering how do i change them to better quality?