Is it possible to use conditional logic to automatically calculate quantity or amount for Square products field.

I'd like to automatically populate the amount field inside "My Products" within the "Square Payment integration. I'm wondering if this is possible. The only summary field that I see under conditions -> calculate -> "do" is "My Products" but whenever I select that summary field, it doesn't seem to do anything. 

You need to first setup your products, where you will need to perform the calculation: https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget 

And once you get total, pass it to your Square payment field as shown on this guide: https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field 

Let us know if you need more help.