To access your SMU Astronomy and Physics @ap.smu.ca email account via a web-browser visit: www.ap.smu.ca/apwebmail. This will take you to the login screen.
Login to the site with your Linux username and password. The first time you login, there are a few settings that you should change. Select "Settings" at upper right, then "Identities", then select the one identity listed. At right you can enter your personal information, in particular your full name, which is displayed when you send email. After you have entered your personal information, you might want to explore other available settings.