How to add a Payment option

Click the E-COMMERCE button in the main menu
Click the PAYMENT OPTIONS button found under payments and tax section
Click the currency button inside the required payment option
Add the required credentials (username/merchant ID/secret key etc and save
Test the payment gateway with a small purchase to ensure the credentials are correct and money is being received.

Note: if your site is not live, the payment will succeed, but the call back to the website to mark the order as paid will not.

Click the SETTINGS button next to each gateway to change the settings.