You can start here, read this section when you need it, or ignore it completely. How's that for an easy-to-get-along-with book? If you read the book introduction, you'll already know that this Key Concepts section is intended as a reference you can use if and when you need it (if you didn't read the introduction, this Key Concepts section is intended as a reference you can use if and when you need it).
So it's up to you: read through this entire section, or jump right into the individual techniques and come back here if you need to. Just about all the techniques start with icons that represent the key concepts used in their steps, so if you need some clarification or background information, you can come back here for a little help.