Dave,
Here is the direct link to the Chapter 3 flash video:
http://www.graphisoft.com/ftp/marketing/ac12/nft/03-3DD-03/03-3DD-03.html
The videos can be viewed on the link I posted earlier by scrolling down to the appropriate section and clicking on the link next to the image. The videos are also included in the ZIP file download link for eachsection, along with the tutorial .pla files. I see that you are using the Start Edition though, so you may not be able to open the files.
I find the 3D cutting planes to be invaluable in presentation, model exploration and 3D documentation. You can get some really cool results in a short amount of time. Perhaps if you spend a few minutes with 3D cutting planes you will start to see how easy they really are, you just have to understand the way they work. One tip is that you can define your x,y or z values by clicking the corresponding icon and typing your value. For example: if you want to eliminate everything above your first floor from view, click the "z" icon and type the upper height limit of your first story. Voila! Everything below this z-level is visible, the upper stories are hidden.