The official way to start is to use make the chicken soup on page 89 (May 2010 edition of BTVC) and eat only that for two days. The book does not have stages of food and some use the stages on the website www.pecanbread.com.
For various reasons, some of us just started without the official Intro. Start with cooked, peeled and seeded foods. Roasted meats, poultry and fish and steamed vegetables. Zucchini, carrots and green beans are popular starting vegetables. Try a small amount of a new thing. Wait a day or so and try a little more, etc. If all goes well, add it to your safe food list. Well ripened bananas -speckles on the skin and no green - are handy and satisfying.
The original diet developed by Dr. Haas had so many bananas that it became popularly known as the "banana diet."