Underneath the 'Log-in' button, click 'Forgot your password? Click here to reset.'.
On the next screen, enter the email address you use to log-in and click 'Reset Password'.
You will receive an email with your new password which you should now use to log-in. Please check your spam folders for this email if it does not appear in your inbox within 5 minutes.
To change your password to something you will remember, click on the three lined cog in the top right hand corner of class charts and scroll down to 'Account Settings'.
You can now change your password to something you want it to be.