Multi input slot furnace issue

so, this is the gui im using, and its working but not like i want to, the output item replaces the slot 02, and the procedure im using doesnt have timer, so the output item cames instantly, and the thing is that replaces the amount and the input item on the slot 02, i cant figure it out to make a functional 3 input slots furnace

https://drive.google.com/file/d/1s-0RjG98KIpPlnORMXk9-xlMaBariVax/view?…