If you're still confused, I just did. Here's the steps I had to take:
-Free Server City from the super strong MetalGreymon (I had to get a mega)
-Recruit Xiquemon to City
-Complete every challenge
-Recruit Publimon in Sewer Road
-Help Medicmon in Drive Savannah (he needs a rainbow soup, which takes a rainbow trout, which you get with a crayfish lure)
-Cure Minomon and Kudamon
-Battle Paildramon
... This game could really use better conveyance.