Do you want your entire scene in focus but what you end up with is either the front (closest to the camera) or back (furthest away from the camera) of your picture in focus, but not both?
How much of your scene is in focus is called 'depth of field'. DOF is affected by two things - the aperture of your lens and where you set your focus point. If you want all your scene to be in focus, you need maximum depth of field.
Here is a really interesting article that might help you gain more control of your depth of field/area in focus