After you've already had us purchase and install your SSL certificate, and have created an account with Authorize.net:
1. Choose to Create New Payment Method. Select Authorize.Net as the Method Type.
2. Name the method ("Pay by Credit Card" or similar)
3. Enter your API Login ID and Transaction Key. These were assigned to you by Authorize.Net.
4. Check the Test Mode box. Make sure to confirm with Authorize.Net that your account is in test mode at their end as well. Save.
Next, go to Sites > Settings > Payments tab,
1. Turn on this method for the site by clicking the box next to the payment method name.
2. Authorize.net requires an SSL certificate be applied to the store's domain (URL / web address). This must be purchased and setup by Aleyant before the store can use Authorize.net. If Aleyant is not hosting your domain (it is being hosted elsewhere such as GoDaddy, Network Solutions, Register.com, etc.), make sure to point the domain to your Pressero secure IP issued with your In-Store Credit Card Processing for your Pressero account.
3. Test the Authorize.net setup by running an order through the storefront. The checkout should simulate a successful checkout and credit card charge. If you get an error, one of the items above is not set correctly. Double check them, make any corrections, and test again.
4. After the test is successful, contact Authorize.net and have them turn off the test mode for your account. Then create a new payment method with the credentials (Preferences > Payments > Authorize.net), and leave Test Mode unchecked. You will need to set your site to use the new payment method.
5. Test a live transaction. Place a real order with yourself. The credit card should be charged successfully.