on cheatplanet it says you can get adragonball by beating nappa the first try i did that and i didnt get one,can someone tell what im doing wrong?

You get one dragon ball at the start of the game, after that u do story mode or world turnament to get money, you go to Mr. Popo at recomended and the Dragon Balls are grey and they cost 8 000, you just have to go in and out untill you get all 7 dragon balls, after that u may chose 1 from 3 characters (if the character u whant isn't on the list u just restart) or a Brakethrough Capsule (u put it on a character and it has all the things on it, except green stuff).