Hi Angaria and welcome to our community
One thing you can try is to click Audio > Edit timing...
and simply adjust the slider positions to adjust the split points
for slides 6, 7 and 8.
Also, I totally agree that Captivate is way easier to use
than Camtasia Studio. (I have both applications available to use
and compare) Each application has its own strenghs and weaknesses,
so I can easily see authors wanting or needing both.
Cheers... Rick