How do I make one item have multiple textures?

[ConnoR]

Hello! I need help

[ConnoR]

I accidentally pressed enter on the first reply
So I have a command block chain set up that makes a carrot stick into a gun
I want to make a texture for it but when I do that it removes the default texture as well
I've looked up how to make items with tags have textures but I can't find anything.
I really would appreciate someone helping me with this

Thank you for taking some time to read and respond and have a nice day.