Fb = M/S?

Fb is “extreme fiber in bending” or basically a moment? and it is in lb/in^2 (it is a force). S is section modulus in in^3 and it is basically a given number from the charts (or it is derived from the equation in the title (Fb = M/S)? and it is a “geometric property” of a beam? but it is independent of material properties is that right? M is maximum bending moment in PSI or pounds per square inch? - so i can be given an actual S for an actual beam (or have to look it up in the chart) and i can be given an actual bending moment? and then i would compare this to - well i would simply be able to calculate the actual extreme fiber in bending at that point in that particular beam assuming i was given the moment at that point? or i can rewrite the equation S = M/Fb and i would be given an actual moment at that point in the beam and i would be given and actual allowable Fb for that MATERIAL (or i would look it up in the chart?) and i would determine whether S was sufficient to support the given moment provided? i mean conceptually are there any structure ninjas that can help me break this down? THANKS