You need to be at Level 55-100 to do the party quest. This PQ is also known as the Pirate PQ.
For a complete video guide of this PQ, click the Play button above (thanks to AionJC).
Head over to Herb Town: Over the Pirate Ship and gather 3-6 players to form a party.
Before completing the Party Quest, it is recommended that the following quests are initiated as the PQ will help the quests to be completed:
Your party leader should talk to the NPC Guon to begin the quest.