If your Australian and using PayPal

I am having a bit of trouble setting up an account. Got the personal info done but I am up to adding the debit card information. I am using my Commonwealth Bank bank card. Theres 17 digits on the front and then PayPal asks for 3 security digits in the back, theres nothing on the back, just the black strip and my signature… :puzzled: I tried typing all 17 digits in the “credit card” field but says i am “missing digits”. Could I get help please?