Hi fredchoum and welcome to our community
I'm not sure what a diaporama is. I did conduct a Google
search and looked at Wikipedia, but returned empty handed. Based on
your context, I'm guessing it may mean "Slide Show"?
What version of Captivate are you using? If it's version 3,
you should have an option to automatically advance the slides or to
use a Click Box object on each slide. If you would like to add
buttons, just add a single button on slide 1, configure it to go to
the next slide when clicked. Then copy the button, select all the
other slides, then paste. The button should be placed on each of
the other slides in the same position as where you copied it from.
Hopefully this helps a bit... Rick