Quests

Quests are great, they give you money, items and tons of experience; they also give your guild points.

There are several types of quests:
Killing quest- You just kill the required digimon. In some cases killing the leaders won't fulfill the quest or you have to kill only leaders to fulfill it.
Drop quest- Where you kill digimon and wait for them to drop a required item, these quests take the longest and can be frusterating.
Delivery quests- Where you have to take an item to an NPC or you just have to speak with them.
Use quest- Where you have to go to a certain place on the map,NPC or digimon and " use" the item on them. You do this by clicking on the target and left clicking the item you need to use on them.

Here is a guide that is in detail for all the quests up to entering the Digimon Maze.

http://englishdigimonmastersonline.blogspot.com/2011/08/quest-guide-1.html

As for the quests in the Maze itself, I found a guide that is in rough english that I'll try to clean up and post as soon as I can. Here it is if you don't mind the rough translation or can read Indonesian.

http://story-games.blogspot.com/2012/09/quest-maze-entreance-b1-b2-f1-f4.html