After setting up your gateway, many gateway systems will send you a user name and password to access their system. For most gateways, including Authorize.net, all you have to do is enter that information into Spark Pay online stores . Check out the related links below for more information on payment gateways.
Go to Settings > Payment and Taxes.
Make sure that the "Accept Credit Cards" box is checked. 
This will allow you to take credit card information. Even if you do not have a gateway, enabling this allows you to gather card information and process the transaction manually from a terminal or other such machine.
Go to Settings > Payments and Taxes > Payment Gateways.
Select New to add a gateway.
Under Add a Payment Processor, select the payment gateway you would like to use, and select "Add" in the top right corner.
You can add multiple processors and set different processors for different stores. In order to use any one of these gateways, you must first have an account with that company.
The screen will refresh with a place for you to enter login information, cost modifiers, and more. You can also have the gateway set to "Authorize Only," which authorizes the card but does not charge the account. 
Enter the information and settings for your gateway and Save the changes.
Very few gateways need our technical team to install software on the servers, but we can do this when needed.