How do you beat the great maze on Super Smash Bros Brawl?

You have a map that you can look at and if you see like a red dot i think (I haven't played it in a long time) you go there and go through the door that's all black and purple and beat up what's inside. Inside will be a character in the game and you have to beat every single character. After you are done with that, You will have to kill Tabuu (The most powerful video game character in the world).