This book was designed and written both for people new to Perl/Tk and those who are familiar with it. How you approach the book depends on which category best describes you.
Perl/Tk novices should probably start at the beginning. This book is designed to lead you into topics by building a foundation of knowledge. We'll start with a Hello World example in Chapter 1, "Hello, Perl/Tk", and from there move into geometry management and the standard widgets. Using Perl/Tk is not really that hard once you understand the fundamentals of how it works.
Experienced programmers should feel free to skip around at will. We recommend reading through Chapter 2, "Geometry Management" so you have a complete understanding of how the geometry managers work. Then skip around to the different sections in which you are interested. This book has quite a few examples that will give you ideas on how to use Perl/Tk in different ways.