Here's the step-by-step:
1. Top up your Paypal account
Your account should have around 5 USD for verification purposes from PayPal;
2 Use Paypal to add your details
Incorporate the card details in the PayPal app and follow the steps.
3. Double-check your billing address
Billing information will be the same as your current billing address.
In case the account doesn't link to PayPal, just reach out to Paypal directly. Keep in mind that not all transactions or card additions go smoothly.