You can access your Olivet email account by logging into My Olivet. At the top of the home page you should see a button labeled "Access Outlook email." Just click that button to be taken to the email login page.
You can also access Olivet email directly by visiting email.olivet.edu and entering your full Olivet email address (<username>@olivet.edu) and your email password. If you are a new student and have not yet changed your email password, you will use the default password given to you when you received your account details.