Break-ins are random, so you could get it within a few matches to a hundred matches. For the fourth step, I'd suggest running too. If you did it right, a red dot will appear where the World tournament is. You have to just do all the main points up until the point you fight Kid Buu.
For the first and second steps, you can fight, but not too much. Go to the islands next to the dot and go to the. The fourth step is the longestor at least it seemed that way to me, so even if you feel like you can fight it's probably not a good idea. But once you do, have Kaioken, Super Saiyan, and Spirit Bomb as the required skills. Then you fight him, win, then unlock him. The slimmer, more toned version of Majin Buu is his ultimate form. Here is a collection of cheats, codes, and hints to play this popular fighting video game. I know it seems cowardly not to fight at all really, but if you want to beat it then I suggest doing it this way.