This effect is created by anchoring buttons into the text and marking them as being ScrollActions.
1, create the slide show.
2, create the text frame and anchor the buttons.
3, add the buttons. Position the buttons out of the text frame so they do not alter the flow of text.
4. create the container for the scrolling text.
5. paste the text frame into the container.
6. assign actions to the buttons, here we use goto state. ( this must be done after the paste )
This image shows the text frame with the buttons and the buttons dialog showing the action. The scrollactions.txt should be selected.