What are the tasks and how do you get them? Because I found the "Task Log" but there's nothing there. Can someone explain this to me?

"Tasks" are the "missions" found in the land of Astryl's Vale in the Kingdom of Eternia. Basicallly, the missions you can undertake in Eternia/Astryl's Vale are the "tasks" that will be listed in the task log once you accept the quests/tasks/missions in that area.

The difference with these 'tasks' is that you have to undertake them yourself with your sylesties instead of simply sending a chosen sylesti to complete it. It's a more hands on mission.