As a new, and possibly small business, you may find it too expensive to set up a merchant account with your bank, let alone be authorised to have one, as in the banks eyes, you may still be an unknown, and there are risks in accepting credit cards with a new merchant account. Assuming you had all that approved, you would still need to integrate their merchant system into the website you have, and that requies comprehensive understanding of HTML computer language, and website editing abilities.
A much simpler way to go about this is to use an online payment processor from a third party. There are numerous options available, that charge reasonable fees, typically on a 'per transaction' basis as a percentage.
I will refer to two options, namely Alert Pay or Pay Pal.
Both these providers are available in most parts of the world, but you will find Alert Pay is more easily accessible in some East European countries as well, whereas Pay Pal is a little more choosy.
The idea is to go to their respective websites, and establish an online account. This is relatively straight forward, and can be done with minimal fuss.
Once you have progressed through this stage, you will need to provide valid identification, to protect both you, and the processor. This is in the form of providing a bank account number you would like the funds you earn transferred to, or a valid credit card. In the case of Alert pay, you will also need to forward a copy of your driver's licence or similar. Again, this ensures you are protected, and is a one-time process.
When this is all set up, you are then able to create buttons, in the sense that you need to assign each product on your website a monetary value and item name, so that you will then be issued with code, to place on your website. This can be handled by your webmaster if you are not technically minded.
The idea again, is to ensure that you have a simple system to put in place, to get you on your way to moving your new website economy in the right direction. Most people will be able to set this up in a matter of a day, or at most, with verification, in a matter of two or three days.