The first thing you should do is login and familiarize yourself with the system.
Next, and most important, is to get your tracking link. The tracking link must be clicked/visited by someone in order for you to get sales credit. It's how we track which affiliate gets credit for an order. Please see the above video on how to get your tracking link.
You may wish to shorten your tracking link (this is completely up to you and is not a necessity). You can do this with any URL shortener service such as bit.ly. Benefits of shortening your link include a) a cleaner link b) if you use the link in several video descriptions, if it ever changes, you would only need to update it once in the URL shortener service.