Jaza,
AS will help hide your interest in a particular item until the last few seconds of an auction. Why is that important? The same reason a company's stock goes up when Warren Buffet decides to buy them. It's basic supply and demand. The greater the demand, the higher the price.
AS won't win auctions for you unless your bid is higher than others bidding. What it will do though, is not let them know until the last minute so they can't change their mind and outbid you.
Welcome to the forum and to AS. I recommend you read through the forums, check out the help section FAQ's and select a low dollar item to bid on first. Once you win something, you'll see how well the system works.
Good luck and Happy Sniping!
<-M->