So if per the chart you set your camera at say F8 with a film EI of 100 to place the subject properly when 8' from the camera, then you would them adjust shutter time to place the background properly per your meter.
Keep in mind the limitation of synch speed with the FM2n is 1/250 or below. Above that you will have partially exposed frames. For experience, I'd shoot a frame at each higher speed to see this effect.
Not that anyone here has EVER used the wrong synch speed.