Hello,
To implement the equations you will need the distance module distributed with the Developer and Platinum versions of the plugin. To get the distance between two address, assuming that the fields for addresses are: fieldname1, and fieldname2, the equation to use would be:
DISTANCE(fieldname1,fieldname2,'mi','DRIVING')
If you want get the distance in kilometers: DISTANCE(fieldname1,fieldname2,'km','DRIVING')
If you want create a more professional form, I recommend you the Platinum version of the plugin that includes the “Google Places add-on”. This add-on allows to convert the addresses fields in autocomplete fields associated to Google Places, when the user start typing its address the plugin will display a list of matching address based on the text.
Best regards.
