Camera in the object

I've been tutorial of rolling ball. They had this trick, which would look for parent's horizontal and vertical axis and camera would follow it.

I thought I would be building an FPS game over time, step-by-step, but I couldn't get idea of:

- How would mouse command camera where to look.
- How do I get my object to move to place that I'm facing instead of going to it's relative "front".
- How do I even put camera in the object so that it will be as if the object had eyes, without putting camera...

Camera in the object