Buddypress Formidable forms

Hi, I’m new to this and I’m really stuck. I have created a form with formidable forms, when I save a post I would like the buddypress group name for the logged in user to be saved in a field.

I do not know anything about coding so please keep it simple.

Something like: http://prntscr.com/mc3mau , but it should work also:)

help please…

KR
Andreas