I need someone to teach me how to set up Google distance matrix in Fabrik form element on Joomla

I require someone to teach me how to go about setting up Google distance matrix on an element calc in Fabrik on Joomla. I have a form with 2 dropdowns. 1. Start 2.End. I want to use the selection made to calculate the driving distance between the 2 points and then save the result in the record field. I have most of the work done but am clearly missing something. I need an expert to go over my code and teach me where I am going wrong. Low priority, low budget job. Really just beer and burger money for some benevolent soul wanting to help a fellow developer.