1. They work by setting a global variable to the value of the current component then calling the render function. Whenever you call a hook you're effectivelly dispatching it to the component in question, OOP style.

2. React counts the number of executions of (certain) hooks. This count is how it knows which state to get from the store as a return value from `useState`. useState is effectively `getStateAndSetter()` but it doesn't pass a key name of any kind, so the implicitly passed key is `hookCount++`. This is why you can't call hooks conditionally, or state would get all messed up - if a condition turns false and one hook doesn't run that render, all getStateAndSetter calls that run after it will be off by one.