Button properties

Hi,
I'm beginner with Xerte.
Can I ask you for help with using button object?
I used the icon button, but I can not dynamically change the properties in the script (label, enabled, visible). Could anyone advise me how to access to the subject?
Will I have to put the "button" icon on every page?
Can I put it on "interaction" icon (in file *.rlt)?
From which site (script or event) I can refer to a button, to change its properties?
Thank you.