If I have check boxes (or radio buttons) with values of $20, $10 and $5, how would I get that value to populate another field? For example: the 3 check boxes are shipping rates. Once one of them is selected, I want that amount to populate another field that is part of a "total" calculation (i.e. items + shipping = Total).
Under Calculate, select "Value is the (sum) of the fields..." and then
select just that one field.