How did the Crusader States in the Middle East function politically?

I know the Kingdom of Jerusalem is the one that most people are aware of, but for some reason the three other Crusader States like Tripoli, Edessa, or Antioch seem forgotten and barely mentioned. Often times Edessa is the only one that gets mentioned because it was the first to fall, but that’s it. My question is, how did the governments and political systems work? What leadership did each of the states have? What, if anything, bound the states together? I feel like there is a whole lot more to the Crusades than just the Battle of Jerusalem