Your customer ID and password were provided when you purchased the license. The Customer ID can be found in the About SQL Detective window of the program.
When you enable the auto-login feature, a cookie will be placed on your computer that identifies who you are to the SQLDetective website, so that you do not need to type your customer id and password each time you visit the site. Do not use this feature on a public or shared computer, as other users of that computer will be able to access your account.