Ludibrium Maze Party Quest
You need to be between Level 51 - 70 to do the party quest
(Note: There are no actual stages in this party quest, but for the purpose of this guide, the vast majority of this quest will be placed under 'Stage 1'.)
Head to Ludibrium and climb up to the top of the clock tower, either by manually climbing up or by accessing a warp point at the bottom of the clock tower next to the storage NPC. You will need to form a party of at least 3 members.
While there are no actual recommended characters to have, having someone who could deal massive damage (Warriors with Slash Blast), someone who could heal (Clerics), and someone who could cast Haste (Thieves) would be a bonus.
Also, the amount of party members you have depends heavily on the party members themselves - the more party members you have, the harder it is to keep track of everyone in case a person gets lost, while the less party members you have, you will have to deal with the danger of falling beneath the "at least 3 members" requirement (failing which your party will be disqualified), in case any party member accidentally gets disconnected.
Your party leader should talk to the NPC Rolly to begin the quest. There is a time limit of 15 minutes.