How do stats work?

Is there a handy link or something, because it's all a bit arcane to me.

For example, Princess Leia. She has one basic attack called Hair Trigger. According to swgoh.gg (https://swgoh.gg/characters/princess-leia/stats/), her Physical Damage is 2712.4 and her Special Damage is 1608.0. First off, I'm going to assume special damage is irrelevant for Leia, because she doesn't have a special attack. But besides that ... What does 2712.4 mean? What mod stats modify it, and by how much? Does Offense give 1 extra 'damage' per point? 2 extra damage? Does agility do anything for physical damage? How does "2712.4" translate into a 25k crit (which would presumably be around a 10k normal hit).

What does Defense do? Does each point of defense negate a point of damage? Is it possible to do 1 point of damage if you get Defense high enough compared to a characters offense?

I'd like to dig a bit more into the guts of SWGOH (truth dropping time - I'm looking to do a definitive list of 'average basic attack damage', and figure out for specific characters if offense or crit damage is better, because I like this game and I like numbers), and have a better understanding of how stats work is pretty much a prerequisite for that.