How to become a referee in the US

[italian_referee]

Good morning everyone!
I am 25, I am from Italy, and I will move to the US (Philadelphia, PA) next July.
I have been a referee for the Italian Basketball Federation since 2008, where I came to be eligible to referee in the Fourth Italian Senior Division.
I am writing in this forum since I would like to continue refereeing also in the US, but it is not clear to me where to start, and I would need some help!
If you were so kind to answer a few questions, I would really appreciate it:

• Given that I am moving to Philadelphia, I had a look at the Pennsylvania Interscholastic Athletic Association website. Is that a good start?
• Is it true that one starts officiating at the high school level?
• How does one advance to higher levels? In Italy referees are evaluated on the basis of quizzes and officiated games, and at the end of the year there is some kind of ranking, and the best gets promoted onto the next level (i.e. from the fourth to the third division). Does that happen also in the US?
• Is it possible to officiate in the NCAA for example after a few years of experience?
• Do you usually have games in one state or is it possible that one needs to travel from one state to the other?
• Are referees paid?
• Which kind of rules are followed? FIBA ones? Do they change from association to association?
• Does one need to referee a very large number of games per year to advance his career as a referee?

Sorry for the large number of questions but I have really little idea of where to begin, and even after several searches on the internet I could not find very useful information! Any kind of help or information on how things work would be really appreciated!

Thank you all!