Junior quest follower Achievement
Junior quest follower5
Complete 10 quests
You will get this pretty early on in the game, as there are tons of quests to do. You can see how many quests you have completed by clicking on the achievements icon (the trophy) and going all the way to the left. Quests can be anything from training a unit, placing a building or buying wood. Most of the early ones are pretty easy as you will either have what is required to get them done and can place/train/buy etc what you need quickly.