You can access your school emails online at https://portal.office.com and logging in with your school email and password. You can access many other office applications but we will be focusing on outlook. Once logged in and on the front page, you will see a screen like this:
On the left hand side there will be a bar of applications, the one you want it highlighted below. If you cannot find this, click the "+" button to find it.
Once you have clicked this, you will be taken to a new page with you emails.