Hey, there's nothing difficult with the book. They explain you very clearly on the two types of custom tags that you can create. Try reading it twice or thrice and I'm sure that you will understand. If still unclear, try out some tutorials by just googling out.
SCJP 1.4, SCWCD 1.4 - Hints for you, Certified Scrum Master
Did a rm -R / to find out that I lost my entire Linux installation!