Ok, I assume you have a flat desk in front of you. Let's start with the centre of the desk as the origin, with an x coord of 0, y coord of 0 and z coord of 0.
From that origin, if you use an x coord that is negative, then that's to the left of the origin. If it's positive, that's to the right. If your y coord is negative, then that's below the origin, while a positive value is above. If your z coord is negative, then that's between the origin and you, while a positive value is the other side of the origin from you.
Obviously, the larger the value in a coordinate, the further away from the origin it is.
The camera is represented by your eyes. Your eyes have a position relative to the origin - if you are sat in a chair in front of the origin, then you have an x coord of 0, a positive y coord (being above the desk) and a negative z coord.
Your eyes also have a direction to look. With DBPro you can specify angles (how much to turn your head left/right/up/down), or you can simply tell it to look at a point.
