According to the creating baloons, I must specify certain text as triggering area. However, I don't know to create that?

Hi Amer,
OK so pop ups... these can either be the defined ones in the objects library or can be any other page object. The pre-defined pop ups are cleaner as they have a close device attached to them and they are automaticlly hidden away when the page starts.. If you use another page object there won't be a close device so you have to make a control on the page to close them and you will have to make the object hidden. (on page load hide object action).

To make one:
Add the pop up to the page.
Pick an object that you want to be the trigger for the show the pop up.
Right click on the trigger object and select 'action'.
In the Action dialogue decide which of the first 6 Events will be used. onclick, ondblclick etc require a user to click the target object. Onmouseover pops it up when the mose moves over the object. just pick what suits the interaction you want.
Now select the ACTION this will be display double click the action and the control parameters appear in the OBJECT LIST.
Either enter them by typing them in OR double click the entry and you will get an entry box.
OBJECT is the pop up, click the button to the right and select it from the items on the page.
DISPLAY will be SHOW
EFFECT is the opening transition, how it appears.
DURATION is how long the transition effect lasts.
When you've done OK back to the Actions list.
OK the Actions list and the pop up is set to go.

You can make some quite neat things with this, play with different combinations of triggers.
It's really simple when you've done it once or twice.

Thanks for the help. I managed to do it.