This is a good question and there are a few answers. Go to the casino website and click on the banking tab. There you will find deposit and withdrawal methods. Click on deposit methods and a page will show how to deposit money into your new account and what methods you can use to do so. You may need to sign up with a specific company such as eWalletXpress in order to have the money transferred to and from your casino account.
Read also our Banking For USA Players article.