Most signature cards come with a transport PIN. You must change this transport PIN to your personal PIN. only then can the card be used. Depending on the signature card, this can also be several transport PINs, which should then all be changed one after the other.
Together with the signature card or in a separate PIN letter, you will have received information from the trust center about which software you can use to change the PINs.
You should write down the assigned PINs and keep them in a safe place. If you forget your PIN, the card can no longer be used - depending on the trust center.