This phrase may seem contradictory at first but in fact it’s quite logical.
Think about road infrastructure for a moment. You have an intricate framework that allows a car to go from point A to point B. How you arrive at point B though can vary depending on the route you take.
Delivering a message can be thought of in the same way. By structuring a speech, you are giving your audience a clear image of what your destination is. At the same time, you are allowing yourself freedom to take whichever route you choose in order to arrive at said destination.
There are a number of ways you can structure your speech depending on the content. A general outline could include an introduction, three key points and a conclusion. Note that having three key points is also an effective way of applying the rule of three discussed in a previous blog post. However you wish to do it, ask yourself if your structure allows your audience to easily follow you to your destination.