Pay at Stadia with a Postbank card?

I wanted to buy a game for the first time today on Stadia (Shadow of the Tomb Raider). However, I only have a card from my Postbank on which only transfers can be made and at Stadia you have to provide your credit card number. Does payment with Google Payments also work with my Postbank card or does this only work with credit cards? In addition, if it should work with my Postbank card, what do I have to indicate in the credit card number box? I'm very confused and need help.

Can't I choose a debit card?

Not on Stadia… Do I have to create a Google Payment Account first and then select a debit card there?

Yes