Yes/no answer with auto field additions?

I am not sure if I understand your query correctly. Do you mean to display some additional fields on the form based on the answer selected from Yes or No field? If so, you may consider consider setting up Show/Hide fields by following the guide below:

https://www.jotform.com/help/316-How-to-Show-or-Hide-Fields-Base-on-User-s-Answer

You may also show/hide multiple fields on the form from the conditions. 

Hope this information helps! Let us know if you are referring something different. We will be happy to help.