You have to take care of your sweet baby, that lives in a house with many rooms where he can receive different kind of cares: dining room, bedroom, bathroom, nursing, study room and playroom. If you click on the baby his state bar will be visible and you will see what he needs. There's 9 types of needs, and if any of them is low your baby will ask for a certain kind of care. For example, if the education level is low, he will ask for books. At the first level you have a single baby, but there will be 2 in the second and 3 in the third one, and the tasks will be more complex. When you start a level you'll see your goals, that means, what level of education, happiness, fatigue or health is required to be reached to pass to the next level. You can show or hide the state bar by clicking on the kid.
If the baby needs education, click on the study room; if he needs food, click on the dining room; you have to deduce what the baby needs from the status of his satisfaction bar: he will be more urged in the lower areas.