[L.B.D.D]

can anybody point me to the right direction for a first time player who wants to reach level 20 in a relaxing manner?

i kind of want to try it out up to level 20 so i can get my hearthstone hero unlocked (yes, you can call me a loser for playing hearthstone)

what job should i pick, and should i just follow a main storyline if there even is one?