For existing users you will need to login with your email address. Then click on your email address when displayed in the top right of the screen and click the “request new password” button under the Log In button
This will take you to the new/reset password screen, simply click "Email reset link and log out". This will forward an email to your registered email with a link to create a password.
An email will then be sent to your email address. Once this is sent, follow the instructions on the email. When you enter a new password, you will be taken to the User Account page, where you will be able to type in your email and password. You will now be logged into the site.