A quick run-down of what the back of your camera is telling you:
M = Manual Mode
1/1600 = Shutter speed is 1/1600 of a second
F1.4 = The F Stop or Aperture. The lower the number the wider the aperture is open. F1.4 is the widest aperture on the 35mm lens I was using. I wanted a shallow depth of field (i.e. all of the background out of focus).
ISO400 = This is the sensitivity of you sensor to light. The higher the number the more sensitive to available light your sensor is.
That row of numbers from -3 to +3 is your exposure. What you're aiming for is to get the little moving arrow in approximately the centre (this is a little simplistic but it's what we'll go with for now).
Like this: Here I've changed the ISO to 200, the shutter speed to 1/200 and the aperture stays at f1.4.
A quick change of settings: Aperture stays the same but the ISO is 400 and the shutter speed is 1/320. Note how the arrow is slightly to the right. I've slightly over exposed this because I didn't think the whites were bright enough.