You simply enter your Twitter username (if you are a protected Twitter stream you will not be able to use the service) and an optional email address. I checked to see why they ask for the email address optionally and no clue is given. I presume for a mailing list.
It will then grab your last 1000 tweets to analyze. Smartly it also says to register for an upcoming webinar while you wait. Great marketing move. As for myself I was told that Monday’s at 10am is my best time. There is a link to tweet that out, of course.