Hi Coniqua,
Let's begin by saying that the audio file for each slide is ONE file. I recorded each speaker's parts in Audacity, and then merged them together into one file there. I then split that file into the file I would need for each screen.
Having said that, I created a second state for each character image I used. I called that state the "Highlight" state. To achieve the glow, I selected the character, and then in the Character Tools > Format option, I selected the little down arrow icon just below and to the right of "Picture Effect." Don't select Picture Effects! Instead, select the little down arrow icon just beneath it. That opens up the Format Picture box. Here are the settings I used. Select Shadow. In Color, select the primary green color - 0/176/80. Transparency = 25%. Size = 100%. Blur = 28px. Angle = 0 degrees. Distance = 0px.
To enact the change, I set a cue point in the timeline whenever the character who is speaking changed from one to the other. Begin the slide with each character in the default "Normal" state. Let's say the slide has a male and a female character and opens with the woman speaking. When she begins to speak, I called that Cue Point 1. Then the man speaks. That's cue point 2. Then the woman speaks again. That's cue point 3. And so on.
Now, it's just a matter of adding some triggers.
Change state of female character to Highlight when the timeline reaches cue point 1. Change state of female character to Normal when the timeline reaches cue point 2. (That takes away the highlight, because now you're going to shift the highlight to the other character.
Change state of male character to Highlight when the timeline reaches cue point 2.
Change state of female character to Highlight when the timeline reaches cue point 3.
Change state of male character to Normal when the timeline reaches cue point 3.
I simply repeat that for each slide. Those cue points come in real handy when doing something like this.
I hope that helps.
CHUCK