Let me start with a couple of things:
1. I also have complained in the past about the documentation.
2. I have successfully downloaded the PDFs and they open normally
That said, the WebAssist documentation has improved enormously and is helpful once you get the hang of things. It is very difficult to write documentation for such a wide range of experience. The only way to learn complex subjects is to just keep reading and experimenting until it starts to make sense.
One of the problems with selling tools is you have no control over the skill level of those that buy them. Just about anyone can walk into a hardware store and purchase a screwdriver and have some level of success using it.
That same person could buy a milling machine with disastrous results. That doesn't mean that there is anything wrong with the tool, the documentation, or the person that bought it. It just takes more time to learn how to use the tool effectively.
The more an extension does for you, the more time you have to invest to learn how to use it effectively. You have a choice of using single purpose tools that are easy to use but limited, or more complex tools that are extremely flexible.
Dreamweaver also requires a good deal of investment of time before you really see the benefits of such a complex tool. The good news is that once you get the hang of how dynamic websites work, and how the WebAssist extensions make it easier to build dynamic pages, you will never look back.
You can use the extensions without coding, but to make make custom websites you will have to know how to change the code to suit your needs. As with all things, the more you know about the task at hand, the easier it will be.
There are plenty of people here that are willing to help. Here are a couple of articles that might help you get started:
10 Tips for getting quick help from a support forum
How to set up a local testing server for Dreamweaver