How to login with LETU email on Ubuntu computers that have been Azure AD joined
When signing into Ubuntu for the first time, click on "Not listed?" as seen below:

You will then type in your LETU email address, being sure to capitalize the first letter of your first and last name (FirstnameLastname@letu.edu). This is because linux is case sensitive when it comes to usernames.

Select the "Microsoft Entra ID" broker:

Then, on another device, go to microsoft.com/devicelogin and put in the login code shown on the computer and complete the login and MFA process.

Once that has completed, you will be prompted to enter a local password for you to be able to login to the computer in the future.