Adding Square is a three step process. First you add the MID as a processor under CRM menu Merchants > Processors. + New, select Square from the processor list within the Credit Card tab, and enter in the fields. Square requires that you use their payment form on your site. Refer to this link in our API guide for directions: Square Payments. Lastly, you need to select the Square account to be used within the site id configuration page. Once complete, you can begin testing transactions. Make sure you select "No" under the Test option for live merchant accounts.