Keep the door closed anytime you are not entering or exiting. Do not open the door for anyone else. Note that your password must be difficult to break so you should create one that is at least 8 characters long and contains numbers or special characters. Now when you login the windows you will need should come up automatically. Press q to quit.
Press b to go back a page.
All of these commands are much more flexible than the simple examples shown here. If you are interested in their more advanced features, consult the manual pages for that command for a complete description. Also typing man intro gives a long list of the standard UNIX commands and a brief description of their functions. Then, type your message. Press return, and you will exit from mail.