I have the manual and go to 'Storyboard', and select a single slide, and double click on the time in the lower left. Nothing happens. Do I not understand these seemingly simple directions? I have clicked many many times.
I suspect you are confusing Timeline Mode with Storyboard mode the indicators to the right above the timeline tell you which mode you will go to, not the mode you are in, see images below.
Timeline Mode - in this case right click the image object and select the option shown below
Storyboard mode you double click the time at the bottom of the object as shown below, which is what the manual is telling you to do.