How do you do master stellar mode in dance dance revolution supernova because i cant figure it out i did what it wanted me too but it didnt say i did it

if you were on the twins heart one that's not the end. i made the same mistake. you have to beat all showdowns on all planets. if you've done so and are now thinking im a retard then i don't know sorry and i probably am a retard =)
-I'm on the first, popcorn, i completed some but i can t do the others all Ive done is 2 showdowns on popcorn if anyone can help???