I want an email if they say yes to a question

This would be done by applying a ‘Logic’ condition to your Send Email Action. There is an introductory article on this here:

https://help.surveygizmo.com/help/use-logic-in-email-notifications

You would start by creating a Send Email Action:

https://help.surveygizmo.com/help/send-email-action

and you would then add logic:

https://help.surveygizmo.com/help/setup-question-logic

I hope this helps you get started!