It tells the reader how to do something.

　　它告訴讀者怎樣去做某事。

　　People even receive training to learn how to do this.

　　人們甚至接受培訓(xùn)，學(xué)習(xí)如何做這些。

　　You see how to do this in the next couple of sections.

　　你將在接下來的幾節(jié)中看到如何做到這一點。