Map User registration ACF field

Hi i am using formidable forms pro , i have create the a forms using user registration addons . In form there is a dropdown field called Gender , I have also created ACF field with field type select . Now i want to map dropdown of formidable forms with ACF field select . I have install and activated ACF addons (by formidable forms). I do not see any mapping options in user registration forms. How do i map this ?

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