❔ Class Diagram Design question

So I am doing this design puzzle in Heads First Design Pattern book. So for those who don´t know this is the solution: Now since I had started my own mini MUD game (just single player console no network stuff) I wanted to implement this Design aswell.(IWeaponBehavior) So far so good. The part I dont understand is how do I connect the Character class, IWeaponBehavior interface with the Item class? Like I also wanna implement different kind of swords aswell which will inherit from the Sword class... Can anyone lend me a hand?