By default, the school auto-listed on your account is “My School”. If you just teach at one school, you may want to leave this the same, or you may want to change it to your actual name. If you will be working with users from multiple schools, you can add all of the different schools.
To add or change a school, go to the Account Settings under the name dropdown in the upper right of the browser screen, then click Schools. Next, click the New button and add the school name.