When you first access the service, you will see a screen similar to this one:
(The text "firstname.lastname@example.org" will be replace with your mail address.) Select a password and enter it twice. You should see this screen:
At this point, you can read the message, print it, or, if there are attachments, download them by clicking on them. You can also reply to the message by clicking the Reply button. The reply screen looks similar to this:
When you are done, you can leave the system by clicking the Close button. You should see a screen similar to:
The next time you log in - either be re-opening the attachment on the initial message or after receiving an additional message - you will see this login screen:
(The text "email@example.com" will be replaced with your mail address.) Now, re-enter the password you selected before. You will then see your message.