How would alt history cultures work?

So I'm writing a story which is basically a bunch of alt history timelines combine and the different nations all occupy one massive world (Like super smash bros of alt history). But the all occupy their territory. Ex- Both Freedonia (Greater USA) and The Imperial Federation have their own Canada independent of each other.

My question is how do I create cultures, how do cultural divergences work.

Any help would be appreciated.
You have 1 message perhaps try written something and see how you feel. Look on a treath abouth idea's you like with a specific divergence that you like and see what that does for the culture. Theirs many books on how to write, but I assume most begin with start writing be critical but not to the point that you stop writing. Explore your intrest and see what you get some will be read some will agree some whill gloss over, look for people you like the input off and don't be afraid to ask their input the worst they can do is ignore you.
Hope this helps
Look at what caused those changes. If Freedonia has a canada (i'll just assume Alberta and west thereof) that likely means it has more of mexico or the caribbean (if the POD is pre cw) which means an increase in latin american music and food, especially if you go with the mexico route. If there were less slaves or back to africa succeeded, bye bye rock and roll, or jazz, or blues