The Chapter 6 lab in this book has three parts, A,B,C. Each part tells you to brainstorm how you would make a tool.
In Chapter 7 it gives you an assignment and tells you to actually create a tool. When I look at the lab answers I see things like "try" and "switch". I cannot find where these were taught in the book. Do I have a different Edition? Were the chapters reordered?
The Try/Catch construct is covered in the chapter on error handling.
The Switch construct was covered in "Learn Windows PowerShell in a Month of Lunches," I believe; it's more like pre-requisite information. But, you're also expected to use the help files in PowerShell – "help about_switch," for example – to refresh your memory, if needed.
I don't have ready access to the lab answer files at the moment, but they should be sequenced per chapter. The chapters haven't been reordered, and there's only been one edition of the book. The earlier chapters' answers shouldn't include concepts from later chapters – at least, nobody's pointed that out to this point, if I did make a mistake there.