Go to Single player, and pick a "player vs CPU" game. Press
at the character selection screen to change the difficulty to beginner. Pick ARIA as your character and anyone as the enemy. Defeat the enemy.
Just button mash through the match and you should win. Mashing
with ARIA is effective and gives a nice combo count. If that's too much trouble, you could also go to multiplayer, choose local play and use a second controller to give yourself a win.