How to make Custom Textures?

[Chilton]

Ive been recently attempting to make a set of modified textures for a Custom Story im working on - As it is, i have a file in the story's folder, which contains the edited files, but i cant seem to get the retextured items to actually be appear retextured in the game.

Either im doing something wrong, or im not doing something at all

Any assistance is much appreciated