There's 1 campaign, split into 3 "Acts"
I'm not sure if they incorporate different civs into it, or if you play the same civ thruout, it might be something like in Age of Myths where you play a single campaign but swap 'gods' in some scenarios.
My assumption is.. Act 1 is 1 civ, Act 2 is another civ, and Act 3 is another civ...
Never argue with an idiot, they'll drag you down to their level and then beat you with experience.
Preparation can only take you so far... After that you gotta take a few leaps of faith.