You are misunderstanding my statement there, I said I rename it according to the .import file but I don't use Import File because that wasn't necessary.
And for the SIDE SPRITE backhair layer, there is a file for that in the core/root of the APK, but I don't think it works the same as in mod section.
Honestly, I didn't use discord very much because I lost my account with phone number on it. That's why I post the problems here, hoping that the dev notice the modding section doesn't work the same as stated in the general modding guide.