New Mac user - can't login to apple store

I am a new Mac user. I bought a refurbished 5,1 mac pro running mojave. I want to download some apps. I could not create an apple id on the Mac so I created it on a Windows machine! I have signed on to this forum with my appetite appleid so I know the id exists and the password is correct. When I try to download from the app store I get various authentication code on my phone which I told into the app store and then the app store indicates my password is incorrect - which is nonsense since I am using it to write this post or to login to apple through a Windows machine.

Any suggestions as to what is wrong?

Thanks

Clive