You will need to log on to you account on Orange website. then, you will need to subscribe your card. After several days, when they verify the card, you will be able to recharge the balance.
Your password would be your PIN code (4 digit number) that is printed on your contract.
Verification - the credit card you use, they will verify it. From what you write I assume you are talking about a prepaid debit card, they will verify your info with the issuing bank.