As we know that in the alpha test and the first time beta test, and we both find that we can not finish some of the quests in game. Like killing boss or staff. Even we finished F1 ~ F4 mission map. And also can not gather all of the equipment in our level. Why?
Coz we lost one most important instance -- Hero Quest Instance.
If you see a red exclamation Quest Marker, do pick it up. It will unlock Hero Quest instances, as seen below. 2 or more players are recommended, but if you can clear the 4th level instance in a map, then the Hero Quest is really no problem for you.

So after read this post I hope u can get help in upcoming second time test about DGN.
And I will post more guide about how to level up quickly and maybe some Magician guide. (As a 40 lvl Wizard )