VS Battle... in the character selection screen, choose your character by... pressing A while holding down the X... and the gameplay will be done by the computer.
VS Battle... after selecting your character, the screen showing the rules will appear. Choose them and then just press the Start by holding down the Select... and you will hear a different piece of sound effect.
Options mode... Move the cursor to the music... then hold L or R while selecting the tracks... and the number 12 and 13 will appear.
Title screen... when the music starts playing just press L R L R L R... If done correctly, you will hear a piece of sound effect... and the character will be selectable in VS mode.