However, it is difficult to get automatic timing just right, some people read fast, some much more slowly. They can lead to frustration if some are kept waiting for the next slide for too long whilst others find they haven't read everything before the slide switches.
You can set the slide transition to different effects such as 'fade', 'blinds', 'checkerbox'. This can be set up on every slide so that the transition is consistent throughout the presentation, or it can be set up on particular slides only.