Step 1: Open up your web browser and in the address bar at the top of your screen type "login.microsoftonline.com"
Step 2: Login with your full email address and password.
Step 3: Click the Mail Icon
Step 4: Click on "Inbox" to view all your received E-Mails or to compose a new E-Mail click "New" at the top.
Step 5: In order to get to your calendar or other office 365 apps you may have access to click on the box with nine boxes in it at the top left of your screen and select your desired app.