You can read this book from cover to cover if you like, but each hack stands on its own, so feel free to browse and jump to the different sections that interest you most. If there's a prerequisite you need to know about, a cross-reference will guide you to the right hack.
For the most part you can look for hacks based on the multimedia type. Image hacks have their own chapter, audio hacks have their own chapter, and so on. Some topics or programs (such as MPlayer) are too broad to fit in a single hack, so these topics start out with a more general-purpose hack and follow up with hacks that draw on that and add more specific information.
I do make the assumption that you feel comfortable using the command line, editing text files, or installing programs from source or using your distribution's package manager. If you are very new to Linux and find these basic tasks daunting, I suggest you also pick up a thorough introduction to Linux books such as O'Reilly's Running Linux.