how to make a custom trade with a mob

i am creating a cat mod, i want if i right click on my custom entity, i want it to open a trade gui than there will be slot 0 (input) and slot 1 (output), and if i put 64 cooked salmons on slot 0, it will give me an enchanted golden apple in slot 1. i tried this and it didnt work. https://imgur.com/C4Jduip can anyone help me abt this. i really searched it but i couldnt find any results