Ok so here is the basic idea for the card game. It is just like Smash Bros Melee. If you are playing bonus mode that is.
You see, the point of the game is not just to knock your oponent off of the main platform, but you must do it in style. For instance, sending an oponents card to the discard pile by the methods of a KO and fall will earn you 200 points. However if you did it using a pokeball-you get an extra 100 points.
You can play stock, first person to get to a certain number of points. Or you can play time: set a number of turns and the person with the most points at the end wins.