Extractor,
If you are referring to the online AADSAS application (which I believe you are), then the answers to your quetions are fairly simple.
You can't begin the application without setting up an account, and you can't submit the online application without paying the required fees. There are 10 or 12 sections on the online application, and you can just fill them out in order. The final sections involve choosing the schools you want the AADSAS app. sent to, and then making the electronic payment that is required.
Don't stress it too much -- it will all make sense when you being filling it out.
-G