These are the first three missions I finished:
Finn's Plight - Speak to Finn at the far left of the village full of crows and do the mission in the well with him to save Capilli Village.
Pastoral Panic - After finishing Capilli Village, speak to Avo (he has an exclamation point over his head), and he will ask you to save his home. Use the world map to return to the Altar. Travel to the right until you see the beautiful pink tree; kill the spiders around it (I killed three), and Avo will show up to give you a reward.
Bolmus Inferno - In the first house you can enter in the mouse village, speak to Bolmus (a mouse holding a skull), and he will ask you to clean the pests out of his basement. Kill the monsters there and return to speak to Bolmus to complete the mission.