The Pattermakern Pro Fashioner is a CAD tool that runs in the web browser. It is purposely built and only contains the tools that you need for pattern drafting.
The Fashioner is not a beginner's tool. You must have some knowledge of patterns and how they work before digging into this program.
That said, you are more than welcome to play with it to see all the fun things you can do.
Refer to the Fashionier chapter and all of the Fashioner Menu chapters to get started.