Hi, I'm making a layer that goes over the player's head, so far I've gotten the model to render correctly but I don't know what to put in the json so that the texture renders or if I should even make a json in the first place, any help is greatly appreciated

You just need to place your texture file in the correct place, and then reference it from your renderer class...you coul take a look at how other vanilla renderers reference textures for their models