Touya and Minori and the rest of the players in the training camp are hitting a wall with the way they fight.  And Minori's suggestion is that they introduce themselves to one another!
When do use you them? 
When would you like to use them?
Wann setzt du sie ein?
Wann willst du sie anwenden?
Cuándo los usas y cuándo quisieras usarlos.
à quel moment tu les utilises,
tout ça…
Quando le usi?
Quando vorresti usarle?
Quando as usa? 
Quando gostaria de usá-las?
Когда ты их используешь?
И когда бы хотел ещё?