As for training for races, let that come later, especially doing a very structured program. First, keep working on getting in cycling shape and used to handling your bike. Then, do a web search, ask around at your local bike shops, etc. to find group rides for your fitness level. Once you get the basics on group etiquette from here or wherever, go on a bunch of rides. Listen and watch. Get used to riding in a pack. See if a local club offers skills clinics. These are a bonus for racing (bumping, tight cornering, etc.) but not required if you have decent bike handling skills.

As for diet, it's important to be sure you eat and drink enough during your rides once you get your mileage up. Learn to eat and drink without stopping (at least for easy-access food that you might want to have during a race).