As you saw at the end of the animation on the previous page, the person switched back to the regular Text Tool , and then switched back to the Pointer Tool as well. These are important things to remember to do when you are done with the Text Block Tool.
Why? Although the Text Block Tool is handy, you probably won't use it as often as the regular old Text Tool. And furthermore, you don't want to leave the Text Tool active because the only thing you can do with that tool is make text. It doesn't let you select anything.
Just remember to go back to the Text Tool , and then back to the Pointer Tool so that you don't get stuck.