Original Guide From http://maple-unlike.weebly.com/pink-bean-prequest-guide.html

Be prepared for a MEGA LONG chain quest. This prequest requires
a lot of time and patience so work towards it gradually to completion, no rush…

PART 1
Head off to the Temple of Time from Leafre Station and talk to NPC Temple Keeper to get started

You must be at least Level 145 to start the quest.

If you look at the map of the Time Temple, there are three stages (3 Colours)
that contain different coloured monsters at different levels.

The level requirements for each of these stages:

Past of the Vendure Level 145+
Frozen Past Level 150+
Burning Past Level 160+

PART 2
Here comes the hard bit.
You must unlock every map going deeper into the Time Temple.

The only way to do that is, eliminate 333 of the monsters in each map
INCLUDING the three bosses; Dodo, Lilynouch and Lyka.

At the end of ‘Past of the Vendure’ you will need to talk to the NPC Memory Keeper.

Following on from there, you will need to speak with your
1st Job Advancement NPC and talk back to the Memory Keeper

At the end of ‘Frozen Past’ you will need to speak with the NPC Sorcerer.

You need to pay 1,000,000 (1mill) mesos to receive the Sorcerer’s potion.
Use it and attempt to talk to the NPC again.
DO NOT heal yourself before talking to the NPC upon use of the potion.

Reaching the end of ‘Burning Past’ speak with the NPC Record Keeper.

Now be careful, Lilynouch has damage reflect which if you’re not careful enough you may die!

Lyka is able to seduce you so don’t do anything stupid and keep yourself alive

Every time you finish eliminating the monsters in the quest you must go back to the Temple Keeper to complete it to proceed to the next part of the chain quest.

PART 3
Talk to the Temple Keeper once you have unlocked all the maps of the Time Temple.

The following items you will need to obtain are:
10 Smiley Masks – (Memory Monk or Trainee)
10 Neutral Masks – (Qualm Monk or Trainee)            
10 Frowny Masks – (Oblivion Monk or Trainee)
1 Whale’s Helmet – (Dodo)
1 Knight’s Mask – (Lilynouch)
1 Guardian’s Horn – (Lyka)

You will receive a “Marble of Chaos” after obtaining these items. Use it to enter and fight Pink Bean.