Do you must sign into Windows using your school account? This is typically only when your computer is managed by the organization's IT team, then it has benefit of using an organization account to set up the computer, because the centralized contro/admin is by the Entra ID admin user/your IT team.
Otherwise, I strongly recommend that you set up the computer with a local user or your personal Microsoft account, especially if this is your own device. You can still use Microsoft 365 apps on your school account without surrendering your computer to your school's IT control.
If this is indeed a personal device, you need to factory reset it, start over. Set it up with your personal account instead.
To use school Microsoft 365, Please go to https://www.office.com
Sign into your school accoun t. Click on Apps on the left.
Then on the upper right, click on "Install apps". This will now download the installer file. Once downloaded, click on the file to install. It will install the Desktop version of the apps for you then.