I must admit I am floundering a little when it comes to ground combat. I simply have no idea where all the various numbers used are coming from and what effect they are having.

For instance how is advantage calculated exactly? I know some of the factors used by reading the manual but very little concrete data. Does soldiering +10 give you 10 more advantage, 10% more? How does bravery come into the mix? If the enemies advantage is 0 does this mean gas warfare has no effect (as it reduces advantage)? How much weight does technological superiority have? Why does the attacker always have such an overwhelming advantage, even when the defender has better soldiers, technology, etc. (and allowing for air support)?

A few simple equations on how such calculations are made from someone in the know would be greatly appreciated