Rule books are important, but wordy and hard to start with as the outset. Definitely read them but don't fret if you still have questions, some competitors rally for years but don't understand some of the rules (which is unfortunate). Rally university is a great resource to get started, as Richard mentioned. The link is also in my signature.
First off, get out there and see some cars! Get out there and volunteer! If you're close-ish to Team O'Neil you'd probably be able to get out to ESPR which will be later this year as the NASA Rally Sport national final. It'll be a great opportunity to get out there and see how the events function, and MEET Drivers and codrivers, and ask them questions! Now, they're not going to be Ken Block (ie, famous) but they made it there, they can help you.
Unfortunately we're nearing the end of the season and there's only a couple winter rallies (unless you go to Canada, which I wouldn't worry about for now unless you're RIGHT THERE). Things will really start going again in Feburary next year as things thaw out and a few more events get going. Ah! One thing you might do is go to Team O'Neil during one of their rallycrosses, as a lot of stage rally drivers bring their cars out and I know that they're going to have a winter rallycross/ rallysprint.
I started like you once, and eventually found my way into a car, it's very attainable. The biggest thing to know is that rally, in America at least, is a hobby. It's quite enjoyable, and sooo much fun, but 98% of people who do it are spending their own money to go do it and aren't trying to "go pro."
READ the Rally University, and shoot me a message if you still have questions, I'd love to help if I can. Stay in school, and hope to see you out on the stages some day.