How to transfer MS Office license to new Mac w/o an account

I just bought a new Macbook Air, and migrated everything over from my old Macbook Pro. The old comp has an MS Office 2016 perpetual license, and either I never created an account or I have no idea what the accompanying account info is. I tried logging in on the new comp but couldn't find a working account that recognized I had a license. I couldn't find anything about an account or login info in the apps on

the old comp (e.g., there's no File > Account as I've seen noted in other forums on this topic). How can I get my MS Office working on the new comp? TYIA!