Microsoft 365 A3 Education, new laptop setup

Question

Hi, hoping someone can help.

I am not an IT person and my school can't afford one so I am doing my best to help them. We have teachers that all use Word and Excel, so we reached out to Microsoft to get Office licenses and they recommended Microsoft 365 Education. So we purchased Microsoft 365 A3 Education and have setup all the teachers and students as users in the admin portal. I have purchased 30 brand new dell laptops and would like to set them up so each laptop can be assigned to a teacher. When I try going through the setup on the new dell, I type in the email address I setup in Microsoft 365 and it says "That Microsoft account doesn't exist.". I can log into outlook.com and send and receive emails, so why would it say it's not a microsoft account.

How do I make it an account that I can log into the laptop and use microsoft office on it?

We don't have a domain, or really have a need for a domain. The teachers just need to login to the laptop and access Word and Excel. It would be nice if we could setup some sort of admin account on each laptop to login and change the user if they forget their password, or delete the user from the laptop if they leave so we can change it to their replacement.

Any help would be greatly appreciated.

Thanks in advance