I'm rather confused about why the destructive interference formula is (d)sin(theta) = (m + 1/2)(lamda), m=0,1,2,3... instead of (d)sin(theta) = (m - 1/2)(lamda), m=1,2,3...

Unless I'm misunderstanding something, m = to the order. So the first order bright fringe is m=1. However, the first order dark fringe, if you use m=1, you get the wrong answer, because it should be (d)sin(theta)=(0+1/2)(lambda), not (d)sin(theta)=(1+1/2)(lambda) (which is the second-order dark fringe).

Is m NOT the same as the order? Because if it was, the formulas dor destructive interference doesn't work. Mind someone explain this to me? Thanks in advance.