my textures aren't loading

So I've made a texture for a weapon but when I load up the pack, the texture is just pink and black. I've put the texture in item/filename and updated the .json file to say "textures": {         "layer0": "item/filename"     }, I have also put ```
"overrides": [
    { "predicate": {"custom_model_data":1}, "model":"item/jsonfile"}
   ]
``` into iron_horse_armor. Please help Idk what to do