Microsoft 365 Non-profit Subscription - Where to get Windows 10 product key?

[jhg-goow]

I am an admin for a non-profit account. We have licenses for Microsoft 365, which includes Windows 10/11.  I am trying to install Windows 10 for a user on new hardware, but am stymied.

• I successfully installed Windows using the media creation tool, but it defaulted to Windows Home, and I need to upgrade it to Pro.
• I tried logging in from the newly installed device, with the registered user's Microsoft account, but it complains "That Microsoft Account doesn't exist".  In the admin portal I can clearly see that the account exists.  When I tried using that account at install time it said "You can't use a work or school address here".
• I logged into the admin portal, as the organization admin, but cannot find anywhere to get a product key.

What do I need to do in order to get a product key for Windows 10 Pro?

[#2]

@jhg-goow 

This is exactly the issue I started having in Oct of 2022 and have been dealing with ever since. I have three work machines that all need to be under the same business license-- 2 of them were set up, over the phone, with a Microsoft call center. I found out later in that call she'd had me do it incorrectly. I still need help with this exact issue. 

[#3]

Nobody at M$ seems to read posts here.