Grossly underrated, your camera’s Program (P) mode effectively gives both aperture and shutter speed priority in one semi-automated package. If you want a wide aperture, simply ‘shift’ the Program to get it. You want a slower shutter speed? Then shift in the opposite direction.
The best way to see exactly how the histogram can help you take control of your photography is experimentation and experience. Just go out and take pictures in a number of situations and become familiar with what the histogram can tell you about the results.