Toastmasters, to a large extent, differs from school in that your speech topics is not handed to you, you must choose on which topic you want to speak. Within the manual's framework, of course. Even within this framework, there is enormous scope for potential topics. Think for a moment about the Icebreaker. The topic: yourself. Simple, of course? Not quite. What about yourself do you want to talk about? Your habits? Your hobbies? Your family? Your friends? Where you grew up?
As you can see, even the most simple topic, yourself ;), has lots of possibilities. The aim of this section is to help you brainstorm what your topic will be and guide you to find topics for those assignments where they are harder to find.
The structure is closely aligned to the Communication & Leadership manual assignments (the 2003 version that I started with) and you can skip straight to the one on which you are looking for a topic idea. It is a good idea to make a list of potential speech topics as you go along - it might be an interesting topic to you and might be suitable for another assignment later on.