Headmaster: "You're ready for more dragon riding lessons! Talk to Snotlout. You'll find him near the Fireball Frenzy entrance at the Training Grounds"
1- Meet Snotlout by Fireball Frenzy
Snotlout: "Be prepared to be impressed, [Your Viking's Name]! Welcome to Fireball Frenzy! Gobber and Hiccup made this obstacle course, but no one is better than me. Go in and I'll give you some pointers!"
2- Enter Fireball Frenzy
Snotlout: "Not bad, not bad at all. You can come back and play Fireball Frenzy whenever you want. Right now, go back to the Headmaster."
3- Return to the Headmaster
Headmaster: "Snotlout tells me you did really well in Fireball Frenzy! That's good news."