How would I make a Texture Replacement?

[WhiteGlove]

Simple in theory, but I'd love to replace the textures of clothing from the base game and all the expansions so far. Or, at least the expansions released as a series rather than one big bundle. Vee's Replacements are nice, but I wish it wasn't expansion-less. I get why, though. I can't exactly code, but I can do textures, I can do it pretty well, too. I've contributed on some small mods for small amounts. Unrelated, but I'd be happy to get some pointers