How to ... ?
If you are not logged in you can register as a new user. Alternatively you can get your password sent to you by mail. To use this feature, you need the email address you provided during the registration. Hint: If you forgot your email address, but have a published model, it will be visible there.
You have to follow two links to the user profile input form. There you can alter your password and other personal information. Be sure to provide up-to-date information here, since this data will be displayed in the section "Responsible for this information" in each of your models.