Well, we all came into this world without a clue of how to read music and play instruments, so the best thing is to first get yourself a private teacher. He or she will then teach you how to read and play music. Yes, it's very important to know how to read music and not just play by rote! After that, you teacher will teach you how to apply this to playing flute.
You don't necessarily need to know any "tunes" before you start learning... start out with a beginner's book. It will help a LOT. I recommend the Trevor Wye books. Here's the URL for the first book (there are two of them) through amazon:
i taught myself the basics, so if you get any beginners book, you can learn the basics on your own if you want, then if u really love that, get a private teacher and continue more advanced learning