Add a text zone to your multizone layout by clicking Text or click and drag it onto the layout.
There are two ways to edit the text. You can directly edit the text zone in the layout. The second method is done by select the text zone which brings up the Text Zone Properties to the left. Then click Details:
This pops up a window that allows you to add multiple paragraphs and set the duration of each. Alternatively, you may chose to display and rss feed or a countdown timer.