Black Desert Package on PS4?

I bought a package from BDO on the PS4 and am now wondering how to activate it. I only know that you have to register online on the game page and activate it from there, but how without an existing account?
Can you create a new account and somehow prove that you bought the package on the PS4? Or do I log into steam with the PS4 account?

You can create an account for free and enter a code there.

You can also enter codes for a 10 day trial or so.

Games on PC, at least that's how it works.

None of this has anything to do with Steam.