Once an account is created for you or enroll in the site/course interface, you should receive an email from email@example.com informing that an account was created for you. This email contains a link for you to access the account for the first time and set up your password. It also contains your username, which can be used to reset your password.
The email will look like the image below.
Please check your spam/junk mail if you can't see the email in your mailbox.
Contact John Brumley if you don't see the email or can't login.