Taking credit and debit cards on your e-commerce enabled website requires you to have a Payment Provider to process the ecommerce transactions.
You may want to sign up for a Merchant Account with your existing bank or perhaps you want to use a Payment Bureau who can make things easier for first time online retailers.
Whatever option you choose remember that it takes time - the paperwork is around 5 to 6 weeks, so the sooner you start your e-commerce website the better.