Hey. I'm Mario and let me get things straight. If you are:
a)Luigi, use your punch attack, if done correctly, you will hear a whistle.
b)Mario, that's me, I'd recommend you to use a backward throw. You know how to do that, right? Alright, here it is:
Grab the oppenent with the R button, or Z and A.
Then when you have done that, use the control stick and push it in the opposite direction of which you're facing.
c) Pikachu. Use the thunderbolt, that's B and down on Control stick.
d) Oh, I really can't be bothered anymore. I will write some more in a few weeks time.
For now, Happy Punching!!!!!!