Girocard, contactless payment via NFC smartphone, how?

Do
1

I always pay contactless with my Girocard.
I would like to pay with my smartphone, it is NFC capable. But how do I insert that exactly? I have a normal Girocard and a Huawei smartphone with Android 10

Mi

Which bank? That does play a role.

Most savings banks and Volksbanks have their own app for this.

Other banks require Google Pay and a Visa / Mastercard.