You picked up the book off the shelf or ordered it online, so don't marvel at the attractive black and gold cover, get started! If you've never used Moodle, start with Chapter 1 and then read about creating successful eLearning courses followed by creating your first front page.
If you've used learning content management systems similar to Moodle or have experience with Moodle, browse the contents and then jump in where you feel most comfortable. If you have Moodle available in your organization, get on the phone or e-mail your system administrator and tell him you're ready — get him to set up a Teacher account so that you can name your course and jump right in.
Don't be afraid to make mistakes. There's no such thing as a mistake when you experiment and try something new because no matter what you do, you learn from it. Moodle software is robust and backed up, so you can't really corrupt it. Now jump in and start Moodling.