First, welcome to the forums 
Well, to use Trunks' sword... just play as Trunks and use melee. That's all there is to it
And Ki torpedoes, I assume you mean Kame Torpedoes. This is a new, seperate attack for Goku. It's in slot 7, if I'm correct. Just charge a torpedo using primary fire, and release it when you've charged it enough. Then, when you want to fire it, use secondary fire. You can have 6 torpedoes ready at a time.
But next time, use the Search function. You could have found this that way.
Well, to use Trunks' sword... just play as Trunks and use melee. That's all there is to it
And Ki torpedoes, I assume you mean Kame Torpedoes. This is a new, seperate attack for Goku. It's in slot 7, if I'm correct. Just charge a torpedo using primary fire, and release it when you've charged it enough. Then, when you want to fire it, use secondary fire. You can have 6 torpedoes ready at a time.
But next time, use the Search function. You could have found this that way.